The High Court has agreed to hear a challenge to Australia’s transfer of asylum seekers to Papua New Guinea’s Manus Island. The plaintiff’s submissions raise two arguments. First, they say the offshore processing scheme is unconstitutional because it goes beyond the “naturalization and aliens”, “immigration and emigration”, and “external affairs” powers in section 51. Alternatively, they say that using Manus Island as an offshore detention camp is unlawful because it would not adequately process claims or protect refugees. (This was the basis of the High Court’s 2011 M70 decision to overturn a similar plan to send asylum seekers to Malaysia.) The case will be heard against the background of ongoing investigations into the brutal killing of Reza Barati, and an ongoing tussle over whether PNG judges can order a human rights inquiry into the camp.