Profile

Gregory Wayne Kable, Director of Public Prosecutions (NSW)

Overview

Gregory Wayne Kable was the plaintiff in Kable v Director of Public Prosecutions (NSW) (1996), a landmark High Court case concerning the constitutional limits on State legislative power.

While serving a prison sentence in New South Wales, the NSW Parliament enacted the Community Protection Act 1994 (NSW). The Act authorised the Supreme Court of New South Wales to order Mr Kable’s continued detention beyond the expiration of his sentence if it was satisfied that he was likely to commit a serious act of violence.

Mr Kable challenged the validity of the legislation, arguing that it impermissibly conferred non-judicial functions on a State court in a manner incompatible with the Australian Constitution.

Constitutional Significance

The High Court held that the Community Protection Act 1994 (NSW) was invalid. Although State Parliaments are not bound by a strict separation of powers doctrine, the Court found that State courts cannot be vested with functions that are incompatible with their role as potential repositories of federal judicial power under Chapter III of the Constitution.

This decision established what is now known as the Kable principle: State legislation cannot confer functions on State courts that undermine their institutional integrity or impair their capacity to exercise federal jurisdiction.

The case significantly strengthened constitutional protections relating to judicial independence and remains a foundational authority on the limits of State legislative power in Australia.