Re Coldham;

This matter concerned an application for a writ of habeas corpus brought by Mr. Coldham, who was detained pursuant to a warrant issued under the Migration Act 1958 (Cth). The applicant sought to challenge the lawfulness of his detention, arguing that the warrant was invalid. The High Court of Australia was required to determine the validity of the detention warrant and the scope of the court's power to review such executive actions.

The central legal issue before the High Court was whether the Minister for Immigration and Ethnic Affairs had properly exercised the power conferred by s 189(1) of the Migration Act 1958 (Cth) in issuing the detention warrant. Specifically, the court had to consider whether the Minister's belief that the applicant was a non-citizen and was in Australia unlawfully was a prerequisite for the lawful exercise of the power to detain, and if so, whether that belief had been reasonably held. The court also considered the nature of the review available for a decision to detain under the Act.

The High Court held that the power to detain under s 189(1) was not conditioned upon the Minister forming a belief that the person was a non-citizen unlawfully in Australia. Rather, the section imposed a mandatory duty to detain any non-citizen found to be unlawfully in Australia. The court reasoned that the Minister's role was to implement this statutory duty, and the issuance of a warrant was a mechanism for doing so. Consequently, the applicant's detention was lawful, and the application for habeas corpus was dismissed.