Commonwealth v AJL20

The High Court of Australia heard appeals from decisions of the Federal Court concerning the detention of unlawful non-citizens under the *Migration Act 1958* (Cth). The primary dispute involved whether the period of executive detention authorised by sections 189(1) and 196(1) of the Act continued until the actual removal of the unlawful non-citizen from Australia or the grant of a visa, or whether it ceased when removal should have occurred had the Executive acted with all reasonable despatch in fulfilling its statutory duty to remove. The appellant was the Commonwealth of Australia, and the respondents were unlawful non-citizens who had been detained.

The central legal issues before the Court were: (1) whether the period of detention authorised by sections 189(1) and 196(1) of the *Migration Act* ceases when the removal of an unlawful non-citizen should have occurred had the Executive acted with reasonable despatch, or continues until actual removal or visa grant; (2) whether the Parliament's power to authorise and require detention until actual removal or visa grant is limited by implications arising from Chapter III of the Constitution, particularly concerning the separation of powers; and (3) whether the non-performance by the Executive of its statutory duties erases legitimate non-punitive statutory purposes that those duties support.

The Court reasoned that sections 189(1) and 196(1) of the *Migration Act* authorise and require the detention of an unlawful non-citizen until one of the specified terminating events occurs, namely removal from Australia, deportation, or the grant of a visa. This statutory scheme is not limited by the implications of Chapter III of the Constitution, as the detention is for a legitimate non-punitive executive purpose. The Court held that the Executive's obligation under section 198 to remove an unlawful non-citizen "as soon as reasonably practicable" does not operate to terminate the period of detention mandated by section 196(1) if removal is delayed. The non-performance of the Executive's duty to remove with reasonable despatch does not invalidate the legislative purpose of detention until actual removal or visa grant.

The appeals were allowed, and the orders of the Federal Court were set aside. The proceedings were dismissed with costs, and the respondents were ordered to pay the appellant's costs of the appeals.