Attorney-General of the Commonwealth v CZA19 & Ors; Attorney-General of the Commonwealth v DBD24 & Ors

The Attorney-General of the Commonwealth brought proceedings against CZA19 and others, and separately against DBD24 and others, before the High Court of Australia. The core of the dispute concerned the validity of certain provisions within the *Migration Act 1958* (Cth) that purported to confer upon the Minister for Immigration, Citizenship and Multicultural Affairs the power to make decisions about the immigration status of non-citizens who had been convicted of certain serious criminal offences. The proceedings were consolidated for hearing.

The High Court was required to determine whether the impugned provisions of the *Migration Act* were constitutionally valid, specifically in light of Chapter III of the Constitution, which vests the judicial power of the Commonwealth in the courts. The central question was whether the executive power of the Minister to make determinations that could result in the detention and removal of non-citizens, based on their criminal convictions, encroached upon the exclusive judicial power of the courts to determine guilt and impose punishment.

In his judgment, Gageler CJ reasoned that the constitutional validity of the provisions depended on whether they involved the exercise of judicial power. His Honour observed that the power to detain and remove non-citizens based on criminal convictions, when exercised by the executive, did not constitute the exercise of judicial power. This was because such a power did not involve the determination of guilt or innocence, nor the imposition of a criminal sentence. Instead, it was an exercise of the executive power of the Commonwealth concerning immigration control, which is distinct from the judicial power. The Minister's power was characterised as a power to regulate the entry and presence of non-citizens within Australia, informed by considerations of public interest and safety, rather than a punitive measure. The constitutional separation of powers, as established in Chapter III, did not preclude the executive from exercising powers that were incidental to immigration control, even if those powers were triggered by criminal conduct.

The High Court dismissed the applications for special leave to appeal.