Australia's offshore detention system would be shut down before the next federal election under a series of international deals that will give asylum seekers the choice of resettling in another country or returning to their nation of origin.

The Turnbull government is expected to announce as soon as Sunday a multi-country solution to the festering national sore of indefinite detention on Manus and Nauru, Fairfax Media has learnt.

The plan, which has been quietly worked on as a priority under Prime Minister Malcolm Turnbull, involves individual deals, likely to include the United States, but also a number of Asian countries that have agreed to resettle some of the 1800 boat arrivals Australia has pledged never to accept.

Australian officials from Immigration Minister Peter Dutton down were finalising details and how they should be announced late on Friday.

Australia has spoken to Malaysia, New Zealand, Indonesia and the Philippines as part of the process, but the shape of the weekend announcement was still to be wrapped up.

There is a growing expectation that some asylum seekers will be offered a home in the US, probably in return for Australia's pledge to take Central American refugees in transit in Costa Rica.

Under the emerging Coalition plan, asylum seekers on Manus and Nauru would be presented with two options – accept resettlement or return to where they originated from – according to a government source.

The deal will hinge on the government's move to ban refugees who arrived in Australia by boat from ever returning.

That will force Opposition Leader Bill Shorten to retain Labor's opposition to the lifetime visa ban, currently before Parliament, or buckle to support the resettlements and closure of detention facilities by 2019.

Mr Turnbull has kept tight-lipped on speculation of a deal with the US, but on Friday Cabinet Minister Christopher Pyne spoke of how such a deal could yet be completed before Donald Trump's inauguration.

The government's push for a lifetime ban on resettled boat arrivals ever coming to Australia was taken as another indicator that a third country arrangement was close.

Refugee advocates say the United States would be a welcome final destination for asylum seekers stuck in limbo in Australia's offshore detention system.

While they are split on whether a long-awaited solution has been arrived at, defenders of asylum seekers agree the US would be a "suitable" way to get people off Manus and Nauru in exchange for Australia's promise to take people from US protection in Costa Rica.

Refugee and Immigration Legal Centre lawyer David Manne said the Costa Rica announcement could indicate a swap deal because the category of asylum seekers there is not one that Australia prioritises for protection.

The Hondurans and El Salvadoreans in the Costa Rica camp would be assessed under the little-used "In-country Special Humanitarian visa (subclass 201)" because they have been removed from their own country by the US and are only considered to be "in transit" in Costa Rica, Mr Manne said.

"There are rumours swirling that Australia has struck a refugee swap deal," he said.

"The fundamental and urgent imperative is to evacuate people from their suffering on Nauru and Manus to a safe place where they can rebuild their lives in dignity. The US would clearly be a suitable option for vulnerable people who are stuck in limbo."

Human rights lawyer Julian Burnside said asylum seekers were generally not concerned with which country they ended up in as long as it was a signatory of the Refugee Convention and allowed them to escape persecution.

"Whether it's the US, Canada, Sweden or Australia, their aim is to be able to live without being in fear for their lives," he said.

Ian Rintoul, of the Refugee Action Coalition, welcomed the prospect of a US resettlement deal, but doubted that one had been struck.

"I think people would be willing to go to the US," he said. "They would have to be settled with permanent visas and rights like anyone else. But I wouldn't hold my breath that this is going to happen."

The position of advocates differs from the hardline stance taken by the Greens.

Greens immigration spokesman Nick McKim said the government should resettle those held on Manus and Nauru in Australia.

"Who, in good conscience, could send refugees to Donald Trump's America? We've already seen reports of race-based violence since Donald Trump's election," he said.

"We know his policies around Muslim people and we have large numbers of Muslim people in the camps on Manus and Nauru. It beggars belief."

Senator McKim said Mr Trump could overturn the plan when he took office, leading to more chaos in Australia's immigration regime.

Former Labor immigration spokesman Richard Marles said a US resettlement would be a "fantastic result".

With Tom McIlroy

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