Papua New Guinea's Supreme Court has ruled that Australia's practice of detaining asylum seekers on its northern island is illegal and must stop.
Australia currently detains anyone intercepted while trying to reach the country by boat on Manus Island.
More than 800 people are currently detained there, which the Supreme Court calls unconstitutional and a breach of human rights.
"We now know once and for all that it's not the actions of those innocent asylum seekers, who are coming to us seeking their protection, that's illegal, it is in fact the actions of the Australian government," says Australian Greens Leader Richard Di Natale.
Australia's Immigration Minister Peter Dutton says the ruling won't change their border protection policies and no detainees will be resettled in Australia.
Taking in the 850 detainees at the Manus Island detention centre would be seen as a sign of weakness by people smugglers, he says.