The Turnbull government is scrambling for legal advice following Papua New Guinea's shattering court ruling on the detention of asylum seekers, as Immigration Minister Peter Dutton vows they will not come to Australia.

Mr Dutton said he would await a response from the PNG government after that country's Supreme Court ruled Australia's detention of asylum seekers on Manus Island was illegal, unconstitutional and must end.

But he flagged several other options the government could pursue if PNG concluded the 900 men in question should go to Australia.

"The findings of the Supreme Court in PNG aren't binding on the Australian government," Mr Dutton told ABC radio. "Our policy is not going to change. We are absolutely adamant that people won't be settling in this country."

He reiterated the government's preference for asylum seekers to return to their country of origin, or be settled in a third country.

Fairfax Media revealed in February that Australia was negotiating resettlement deals with Malaysia, Indonesia and the Philippines.

On Wednesday, Mr Dutton said "negotiations [were] under way with a number of countries" and that "arrangements may be entered into" in the future.

But the minister's office confirmed those ongoing negotiations were for resettlement deals only, and did not involve the temporary relocation of Manus Island detainees. A spokeswoman would not comment on the progress of the talks.

What happens next?

Australia will await an official response from the PNG government. Australia is also expecting to receive its own legal advice within the next 24 hours.

Former PNG opposition leader Belden Namah, who brought the legal case, and his lawyer Loani Henao have vowed to take further legal action if the PNG government does not promptly comply with the court's findings.

"In the next couple of days we will be putting an application to the Supreme Court; one is for them to be released and then that the matter be progressed for compensation," Mr Henao told SBS.

Where might they go?

The first possibility is they could stay right where they are. The government could pass laws that make the detention legal, or they could declare the Manus Island detention centre an "open" facility, granting detainees freedom of movement, akin to the facility on Nauru.

Whether either of those options are on the table remains to be seen. But last month, PNG Prime Minister Peter O'Neill said he wanted the detention centre closed and argued it had damaged his country's reputation.

It also seems unlikely the 900 men could be released into the PNG community or taken to Nauru, given the difficulty of accommodating them in those countries, as outlined by The Age's political editor Michael Gordon here.

Could Australia be sued?

The Australian Lawyers Alliance said the PNG ruling paves the way for detainees to sue the Australian government for breaching its duty of care.

"The ruling makes it highly likely that asylum seekers can successfully make claims for damages for false imprisonment from the time they entered detention on Manus Island," Alliance spokesman Greg Barns said.

Ben Lomai, a PNG-based lawyer representing asylum seekers, told SBS he believed asylum seekers detained for several years could be entitled to compensation of more than $100,000.

"If we get the compensation claim, we'll be seeking an order to enforce that against the Australian government," he said.

What are the political consequences?

Labor opened this detention centre and essentially argues it would not handle the issue any differently to the government. But the Coalition, keen to preserve its hardline stance on border protection, insists its opponents would ultimately back down.

"When they're in government they get monstered by the Left and they buckle at the knees," Mr Dutton told ABC radio on Wednesday.

The Greens are pushing for the 900 people stranded on Manus to be brought to Australia, which Mr Dutton has ruled out. Labor wants the minister to travel urgently to PNG for discussions.

Deputy Prime Minister Barnaby Joyce, who was a strong advocate for Australia taking more refugees from Syria, also opposed Australia taking any of the genuine refugees from Manus Island.

"We have clear policy. The clear policy has done this. I understand that some people find it abhorrent but the reality of the policy is… we have stopped people drowning at sea," he said.

"We can't just have any old arrangement otherwise it completely debunks the capacity to both carry the Australian people [with you] and deliver an effective policy forward."

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