Case Note: NZYQ & the Separation of Powers

NZYQ v Minister for Immigration, Citizenship and Multicultural Affairs [2023] HCA 37

Click here to read the High Court of Australia’s judgement.

The Separation of Powers results in a tension between the three arms of government as power is spread between the Legislature, Executive and Judiciary.  Each act as a check on each other, adding more tension as they maintain and curb the power of each other. A key element of the Separation of Powers is an independent judiciary. 

It is paramount that the Judiciary remains unswayed by political pressure from the other arms of government in performing its functions. This is an important part of our system of checks and balances and the Rule of Law. The judiciary’s main goal is not to promote the efficiency of government but to preclude arbitrary power and to make sure any laws made (by the legislature) or actions (by the executive) are lawful. 

The case of NXYQ is a prime example of the rule of law in action in Australia.  In NZYQ, the High Court considered the constitutional validity of laws that allowed the Australian Government to indefinitely detain unlawful immigrants.  


Can the government lock up people indefinitely? What about unlawful non-citizens? We have rules for Australian citizens regarding Continuing Sentences/Detention Orders but what should the government do with unlawful, non-citizens who have committed child sexual assault offences? What if their home country won’t take them back due to their criminal record? Can we permanently lock them up or do we let them free into Australian society? And who has the power to make those decisions?

In December 2023, the High Court of Australia looked at the indefinite detention of ‘NZYQ’, an unlawful, non-citizen convicted of child sexual assault who had completed a prision sentence but, due to his criminal record and statelessness, had no reasonable prospect of deportation back to his home country or any other country. The High Court made a constitutional ruling that the Government can legitimately detain unlawful, non-citizens pending their removal. But, if there is no real prospect of removal in the reasonably foreseeable future, ie they are being held indefinitely, then this form of detention is considered a punishment and not in accord with the powers provided to the Government (Separation of Powers) in the Constitution and is, therefore, unlawful.

NZYQ’s case is important from a Rule of Law perspective. It shows that access to justice is provided to all, even those who are stateless criminals. It shows that the Government must comply with the directives of the Court, even if they disagree with the ruling. It also highlights the protection we have in the constitutionally enshrined Separation of Powers where Ch III courts are the only institution with the judicial power to impose punishments.








The plaintiff, known as NZYQ, is a stateless Rohingya Muslim who came to Australia from Myanmar by boat in 2012. Upon his arrival, he was placed in mandatory immigration detention per s189 of the Migration Act 1958 (Cth). Two years later he was granted a bridging visa and was released from detention into the Australian community. In 2016, NZYQ received a five-year prison sentence with a three-year, four-month non-parole period after he pled guilty to child sexual assault.

In 2018, following his release on parole, the plaintiff was again held in immigration detention per s189(1) of the Migration Act 1958 (Cth). His visa had been cancelled because he had breached its terms by committing an indictable offence, thus, he was once again an unlawful, non-citizen to whom s189(1) appeared to apply.

Two years later, despite recognising the plaintiff as a refugee to whom Australia owed protection, a delegate of the Minister for Immigration Citizenship and Multicultural Affairs (the Minister) lawfully refused NZYQ’s application for a protection visa because he failed to satisfy s36(1C)-(b) of the Migration Act. Consequently, in accordance with s198 of the Migration Act and the plaintiff’s own requests, officers were obliged to deport the plaintiff from Australia as soon as reasonably practicable.

As NZYQ was stateless, i.e., he possessed no nationality/citizenship by virtue of the law of any country in the world; and he had the status of a convicted child sexual assault offender, there was no tangible possibility that he could be successfully removed from Australia in the reasonably foreseeable future.

Procedural History

NZYQ brought the case before the original jurisdiction of the full bench of the High Court of Australia.

He sought leave to reopen the High Court’s earlier decision in Al-Kateb v Godwin (2004) 2019 CLR 562 (Al-Kateb). The Court in Al-Kateb held that indefinite detention of aliens with no real prospect of removal is lawful because it is not punitive and, therefore, does not contravene Ch III of the Constitution.

NZYQ argued that his continued detention was unlawful on two bases:

    • That the proper construction of ss189(1) and 196(1) of the Migration Act did not authorise continued detention in his circumstances (the statutory construction issue); and alternatively,
    • that ss189(1) and 196(1) were invalid because they contravened Ch III of the Constitution (the constitutional issue).

The High Court ultimately held that the plaintiff failed on the statutory construction issue but succeeded on the constitutional issue.

Summary of the Constitutional Issue

1. Separation of Powers in the Australian Constitution

The first three chapters of the Australian Constitution establish the Separation of Powers by defining the roles and responsibilities of the Parliament (Legislature), Executive and Judiciary.

The Parliament:

Under Chapter I of the Constitution, the Parliament has the power to make laws concerning certain areas.

One area the Parliament can make laws for is the naturalization of aliens in s51(xix) which covers immigration detention. Immigration detention is considered different to criminal imprisonment because it is administrative (non-punitive) and falls within Parliament’s constitutionally vested right to control the movement of aliens into and out of the country.

The Executive:

Under Chapter II of the Constitution, the Executive has the power to implement laws.

The Judiciary:

Under Chapter III of the Constitution, the Judiciary has the exclusive power to impose punishments (e.g., punitive detention) for criminal guilt.

2. Precedents for Continued Detention: Al- Kateb and the Lim Case

NZYQ argued that Al-Kateb did not overrule the requirement for a legitimate, non-punitive purpose in Chu Kheng Lim v Minister for Immigration, Local Government and ethnic affairs [1992] (Lim); and, subsequently, that indefinite detention of aliens with no real prospect of removal is punitive and in contravention of Ch III of the Constitution.

The Court was essentially faced with two tasks.

    • First, does Lim remain the authoritative precedent and, thus, warrant reopening the constitutional holding in Al-Kateb?
    • Second, is the continued detention of an alien with no real prospect of removal from Australia fundamentally punitive in nature and in contravention of Ch III of the Constitution?

Did Al-Kateb Overrule the Lim Principle?

Their Honours began their reasoning by explaining the well-established constitutional principle from Lim which concerned the validity of similar provisions in the Migration Act authorising the Executive to manage the detention of unlawful, non-citizens.

According to Lim, valid immigration detention laws must fundamentally serve one of two legitimate, non-punitive purposes:

    • removal/deportation of the alien from Australia; or,
    • the processing of a visa application.

Where detention does not fulfill either purpose, it is considered punitive.

Punitive detention rests exclusively within the jurisdiction of the Judiciary. Should this type of detention be administered by the Executive, then, according to Lim, such an action is in breach of Ch III of the Constitution and should be struck down as invalid.

Their Honours did, however, recognise that Lim’s principle is difficult to reconcile with unlawful, non-citizens who possess no real prospect of removal becoming practicable in the reasonably foreseeable future and who have been refused a visa. [31]

Their Honours then explored how subsequent cases have upheld and followed Lim’s directives and noted the absence of any critique regarding Lim in Al-Kateb. The court also recognised that the Lim principle has been acknowledged and applied in several other recent cases following Al-Kateb [34] and that nothing in Al-Kateb “has been taken subsequently to detract from the significance of Lim.” [33]

Their Honours observed that the constitutional decision in Al-Kateb has steadily become an outlier in the flow of authority stemming from Lim and that this weakening of its holding “weighs strongly in favour of its reopening.” [35]

Ultimately, the court decided to reopen the constitutional holding in Al-Kateb.

3. Does Indefinite Detention Serve an Administrative or Punitive Purpose?

In considering whether the constitutional holding in Al-Kateb should be overruled, their Honours held that it should be determined by reference to its consistency with the Lim principle.

The principle in Lim is that:

“A law enacted by the Commonwealth Parliament which authorises the detention of a person, other than through the exercise by a court…will contravene Ch III of the Constitution unless the law is reasonably capable of being seen to be necessary for a legitimate and non-punitive purpose. In other words, detention is penal or punitive unless justified as otherwise.” [39]

Their Honours acknowledged that consistency with the Lim principle requires that the impugned provisions must include a duration limit to be seen as reasonably necessary to effectuate an administrative purpose. The Court, therefore, unanimously rejected Al-Kateb’s principle which stated that “as long as the purpose of the detention is to make the alien available for deportation or to prevent the alien from entering Australia or the Australian community, the detention is non-punitive.” [42]

The approach of all Justices, except Edelman J (who nonetheless arrived at the same conclusion), was that where no real possibility of removal exists, the purpose of making the alien available for deportation is not practicable and detention, therefore, assumes a punitive nature.


The High Court unanimously reopened and overruled the constitutional holding in Al-Kateb. They held that ss189(1) and 196(1), as applied to NZYQ’s specific circumstances, contravened Ch III of the Constitution. They reasoned that where no real prospect of removal exists or may exist in the reasonably foreseeable future, then detention can no longer be seen as reasonably necessary for a legitimate and non-punitive purpose.

The High Court adopted the recommended outcomes from the Special Amicus Curiae case brought before the Full Court of the Federal Court:

1. It is declared that, by reason of there having been and continuing to be no real prospect of the removal of the plaintiff from Australia becoming practicable in the reasonably foreseeable future:

a. the plaintiff’s detention was unlawful as at 30 May 2023; and

b. the plaintiff’s continued detention is unlawful and has been since 30 May 2023.

2. A writ of habeas corpus requiring the defendants to release the plaintiff immediately.

The Governments Response to NZYQ

The Court’s ruling highlights five essential principles for the Government to consider when enacting future legislation:

  1. Immigration detention should primarily serve administrative purposes.
  2. According to Lim, only two legitimate, non–punitive purposes exist: awaiting removal or processing a visa application.
  3. The purpose of detention must be distinct from detention itself. Holding an unlawful non-citizen, with no real prospect of removal, merely to keep them away from the community is punitive, not administrative.
  4. Where there exists no real prospect of removal and all visa applications have been refused, continuing detention is no longer legitimately connected to an administrative purpose. As such, indefinite detention becomes punitive and should, therefore, only be ordered by the courts.
  5. In our democracy, the Judiciary is the sole arbiter of the Separation of Powers and the constitutional limits on Parliamentary and Executive power.

Opportunities for Law Reform

As of April 2024, 151 people had been released from detention by the Government following the High Court decision. Many of these individuals have been placed on strict visa conditions and the Government has introduced new legislation aimed at detaining these individuals who are threats to community safety.

There has, however, been criticism about whether the strict visa conditions (such as ankle bracelets and curfews) are arbitrary and punitive. If such measures are considered punitive, then it may be expected that the High Court will also rule that the Government has again exceeded their powers and that such conditions are unlawful. As discussed by Chris Merritt in the Australian:

“The vulnerability of this measure has been highlighted by constitutional lawyer Anne Twomey on her YouTube channel, Constitutional Clarion. Because ankle bracelets and curfews are the default position, she believes this suggests the purpose is indeed punitive rather than a protective measure based on risk. “And as we all know, a punitive purpose leads to constitutional invalidity,” Twomey told her YouTube audience.”

Introduction of New Legislation

On 6 December 2023 the Federal Parliament passed the Migration and Other Legislation Amendment (Bridging Visas, Serious Offenders and Other Measures) Act 2023 in response to the High Court’s decision in NZYQ.

This legislation requires that two qualifications be satisfied in order to indefinitely detain an unlawful, non-citizen with no real prospect of removal in the reasonably foreseeable future:

    • First, the Government must persuade the Court that the person it wishes to detain has been convicted in Australia or elsewhere of a crime that carries a penalty of at least seven years in jail;
    • Second, the Government needs to persuade the Court that there is an unacceptable risk that the person concerned will commit a violent or sexual offence – and that there is no other less restrictive way of keeping the community safe.

Proving this to a court will not be easy – nor should it be when it comes to indefinite detention!

Further Clarification from the Courts is Still Needed

The issue of indefinite detention for an alien with no real prospect of removal becoming practicable in the reasonably foreseeable future is far from settled.

The NZYQ decision merely established an initial test for an immediate group of detainees. Constitutional Law Expert Professor George Williams  wrote in the Australian that:

“The legal test will now be scrutinised and refined across a succession of cases over the coming years. This will raise questions only the Courts can answer because NZYQ is based on an interpretation of the Constitution. In the absence of a referendum, this judicial interpretation binds the parliament and government, and cannot be overridden by legislation.”

Subsequent cases will therefore be of great significance because they will address questions about the circumstances in which the Commonwealth can indefinitely detain an alien. For example, questions may include the scope of ‘reasonably foreseeable future’, i.e., is it a month or a perhaps a year? And the scope of ‘no real prospect’ i.e., at what level of probability must a detainee be released?

Analysis and the Rule of Law

1. Operation of the Rule of Law in Australia

Human rights and the Rule of Law are inextricably linked. The Law needs to apply equally and fairly to those in government and to the most vulnerable and disadvantaged in our communities.

Under our democratic system of governance, everyone has access to the justice system, including aliens, refugees and asylum seekers. These individuals are no less entitled than any other citizen to have their matter heard by the full judicial process.

In NZYQ, a stateless refugee convicted of child sexual assault was afforded full access to the Australian justice system. We also see the Government’s compliance with the Court’s directives – releasing 151 detainees in similar situations – which illustrates their commitment to upholding legal decisions.

Like any citizen, NZYQ was held accountable for his actions under the law, and he was also granted protection by the law. Similarly, the Australian Government is not an arbitrary authority but, rather, operates within legal constraints, as illustrated by the High Court’s curbing of its power in alignment with constitutional principles.

This situation holds significance from a Rule of Law standpoint because despite the Government expressing disagreement, it ultimately adhered to the Court’s ruling. The release of affected detainees from indefinite detention highlights the Rule of Law’s active operation in Australia. Despite having its power curtailed by the Court, the Government demonstrated respect for the role and duty of the Judiciary within Australian society.

2. The Separation of Powers

In NZYQ, the Court highlighted its unyielding commitment to the Separation of Powers, as outlined in the Constitution, which serves as a bastion against arbitrary abuses of power. By invalidating laws that infringe upon this principle, the Court upholds the foundational tenet that no one, regardless of their perceived odiousness, should be subject to punishment at the hands of the Government.

This ruling carries profound implications for the Australian legal landscape.

    • firstly, it reinforces a rigid separation of governmental powers and responsibilities; and,
    • secondly, it overturned a 20-year legal precedent by unequivocally stating that only the Judiciary can administer punishment.

At its core, the Separation of Powers serves as a cornerstone of democracy, ensuring that no single branch of Government can wield unchecked power. By distributing power between the Legislature, Executive and Judiciary, the Separation of Powers fosters accountability and prevents the concentration of power in any one institution. In the case of NZYQ, the Court’s ruling serves as a stark reminder of the Judiciary’s pivotal role as the arbiter of justice, particularly in matters concerning individual liberty and the imposition of punishment.

In essence, the Court’s ruling in NZYQ underscores the enduring relevance of the Separation of Powers in safeguarding democratic principles and protecting individual rights. By upholding the Judiciary’s exclusive authority to administer punishment, the ruling affirms the vital role of an independent Judiciary in preserving the Rule of Law and ensuring justice for all people.

3. Balancing Rights of the Individual v Rights of the Community

Balancing the scales of justice means safeguarding both the safety of Australians and the fundamental human rights of unlawful non-citizens who cross our borders. As Lorraine Finlay, Australian Human Rights Commissioner in her interview with the Rule of Law Education Centre rightly pointed out, it is about ensuring that immigration policies are not only aimed at community safety but are also “measured, proportionate and anchored firmly in respect for the human rights of all concerned.”

In this intricate web of considerations lie the following rights:

    • the right of Australia to control its borders;
    • the integrity of Australia’s immigration system;
    • the right of asylum seekers to seek protection; and,
    • the basic right of Australian citizens to feel safe in their homes and communities.

The decision in the NZYQ case underscores this delicate balance and offered an important recognition – that the institution imposing punishment upon NZYQ had no constitutional authority to do so.

However, this decision has, nonetheless left individuals like NZYQ in a state of uncertainty, where their freedom in the community is shadowed by the looming prospect of re-detention should a real prospect of removal become practicable in the reasonably foreseeable future.

While the court’s ruling did not equate release from unlawful detention with a right to remain in Australia, it also has not provided a clear path forward. It is a reminder of the complexities inherent in immigration policy, where the pursuit of justice must be weighed against legal, ethical and humanitarian considerations.


The most significant aspect of the NZYQ case is not just that serious criminals have been freed into the community, but rather that the courts are eager to strike down any law or Executive action that infringes judicial power. If the Executive uses the power of the Judiciary, then not only is the Separation of Powers blurred but a judicial power (imposing punishment) will cease to be wholly open, independent and impartial.

Inflicting punishment is a power that belongs exclusively to the courts, and it is unsurprising that they are willing to strike down laws that empower other branches of Government to punish people, regardless of their citizenship status or criminal history. However, more cases will need to be tested to know exactly where the line is between punitive and administrative purposes so the Government can take appropriate steps.

It is not debated that the safety of Australians should be a priority, however, before berating our judges, it is important to consider whether we ourselves would prefer to be punished by politicians or via an independent, open and impartial court system.

Pin It on Pinterest