The case that was overturned by NZYQ was Al-Kateb v Godwin [2004] HCA 37, in which the High Court held that the mandatory detention of a stateless person under the Migration Act 1958 (Cth) was lawful — even if it meant detention on an indefinite basis. Justice Kirby, in dissent, argued that indefinite detention raised serious human rights concerns and urged the Court to interpret the law consistently with fundamental rights principles (NZYQ v Minister for Immigration, Citizenship and Multicultural Affairs & Anor [2023] HCA 37).
Although in dissent, Justice Kirby’s judgment is widely regarded as seminal for its articulation of human rights principles in Australian law and for highlighting the growing influence of international law on Australian jurisprudence. However, based solely on his dissent in Al-Kateb, one might assume that NZYQ was guided primarily by human rights considerations.
In reality, the decisive factor was constitutional principle — specifically, the separation of powers, a fundamental tenet of Australia’s constitutional law. The separation of powers is, by necessary implication, derived from Chapters 1, 2, and 3 of the Australian Constitution — which establish the Parliament, the Executive, and the Courts. In NZYQ, the High Court’s focus on this principle underscores that, while human rights considerations are important, the structural allocation of powers within the Constitution remains paramount in determining the legality of governmental action.