Plaintiff M96A/2016 v The Commonwealth

The plaintiffs, who were unauthorised maritime arrivals, challenged the lawfulness of their detention in Australia. They had been brought to Australia from a regional processing country for the temporary purpose of receiving medical treatment, but were subsequently detained under sections 189 and 196 of the *Migration Act 1958* (Cth) pending their removal from Australia. The proceedings were brought in the High Court of Australia.

The legal issues before the Court were whether sections 189 and 196 of the *Migration Act* validly authorised the detention of the plaintiffs while they were in Australia for a temporary purpose, and whether the duration of their detention was capable of objective determination by a court. The plaintiffs contended that their detention was not necessary for any legitimate non-punitive purpose for which the Executive could be authorised to detain a non-citizen, and that the length of their detention could not be objectively ascertained.

The High Court allowed the demurrer, finding that the plaintiffs' detention was authorised by the *Migration Act*. The Court noted that the plaintiffs, as unauthorised maritime arrivals, were subject to detention under section 189(3) and that section 198AD(2) mandated their removal to a regional processing country. However, section 198B permitted officers to bring a "transitory person" to Australia for a temporary purpose, such as medical treatment, and the plaintiffs fell within this category. The Court's reasoning implicitly accepted that the detention provisions of the Act could apply even when a person was in Australia for a temporary purpose, provided that purpose was consistent with the overall scheme of the Act, which included eventual removal. The Court concluded that the plaintiffs' detention was lawful under the Act.

The High Court ordered that the demurrer be allowed, the proceeding be dismissed, and the plaintiffs pay the defendants' costs.