The Australian government's top legal adviser has confirmed it may be impossible to resurrect the Howard government's asylum seeker detention centres in Papua New Guinea and Nauru under current laws.
Stephen Gageler has given the government written advice confirming that the High Court's decision to scuttle the Malaysian people swap deal last week has far-reaching implications for all offshore processing.
Mr Gageler and two other senior counsel say Nauru's decision to ratify the UN Refugee Convention this year raises the possibility that it could be used in the future.
But they say this could only happen if the government could satisfy a court there were appropriate protections in place.
Immigration Minister Chris Bowen said the advice confirmed there were significant doubts about both Papua New Guinea and Nauru.
He said the government would now carefully consider all its options, one option being amending the Migration Act.
Under a deal first announced by Prime Minister Julia Gillard in May, the government had planned to send 800 asylum seekers to Malaysia in exchange for 4000 already-processed refugees.
But the High Court's full bench agreed 6-1 that Mr Bowen's declaration that Malaysia was an appropriate place to send asylum seekers was invalid because the country is not legally bound to protect them.
Mr Bowen on Sunday repeatedly refused to reveal whether he considered resigning as a result of the decision, or whether he offered his resignation to Prime Minister Julia Gillard.