Papua New Guinea's opposition leader says he is going to court to shut down Australia's asylum seeker processing centre on Manus Island.
Belden Namah says people can only be detained for lengthy periods in PNG if they have broken the law.
He says the asylum seekers on Manus Island have not broken any immigration laws so they should not be detained behind the centre's high fences.
Mr Namah has engaged lawyers to launch a Supreme Court challenge to the legality of the processing centre.
"To free the asylum seekers who are kept on the Manus Island detention centre, to declare the entire asylum seeker [centre] on Manus Island unconstitutional and have it removed," he said.
Prime minister Peter O'Neill has said the processing centre is being run in accordance with PNG's laws.