Refugees on Manus Island who are not resettled in the United States will remain in Papua New Guinea, with Home Affairs Minister Peter Dutton saying it is a "myth" that other countries will be willing to take them.

Key points:

Peter Dutton says talk of a third country destination for asylum seekers on Manus Island is a "myth"

Peter Dutton says talk of a third country destination for asylum seekers on Manus Island is a "myth" The commander in charge of border protection has effectively endorsed Coalition policy

The commander in charge of border protection has effectively endorsed Coalition policy Mr Dutton again rules out a resettlement deal with New Zealand

The Federal Government has struck a deal with the Trump administration to resettle up to 1,200 refugees from offshore detention, but it is not clear whether all owed protection will be accepted.

Those who are not will remain permanently based in Papua New Guinea under a deal struck by the former Rudd Labor government in 2013, unless another nation is willing to accept them.

Federal Labor has been calling on the Coalition to negotiate another resettlement deal, but Mr Dutton said that was no longer a realistic option.

"Let's be realistic, when Labor talks about some mythical third country, it doesn't exist," he said.

The Department of Foreign Affairs and Trade has been talking with many nations for years but there has been no breakthrough.

Australia has already struck a deal with Cambodia to take refugees, but so far only three people have been successfully resettled there.

Mr Dutton said his staff would continue negotiating but described the prospects of success as bleak.

"People are not jumping out of their skin to provide places, and that is a reality," Mr Dutton said.

"In relation to the Iranians that are on Manus or Nauru, Tehran will not issue travel documents for those people unless they come back willingly."

Mr Dutton has continued to rule out a resettlement offer from New Zealand, saying that will only restart people smuggling ventures.

He has used the example of Malaysian authorities stopping a "sophisticated" people-smuggling operation this weekend, with 131 Sri Lankans en route to Australia or New Zealand.

"Whether they intended to go to New Zealand doesn't matter, people are hearing the message that New Zealand is a prospect for them," Mr Dutton said.

"New Zealand is now being marketed as a definite destination."

Opposition Leader Bill Shorten has urged the Prime Minister to consider the offer from New Zealand, saying it should not be seen as putting people smugglers back in business.

"Australia is not, and must not be, a resettlement option but it is Mr Turnbull's responsibility to work with other nations on resettlement options," Mr Shorten said in November last year.

On Monday, Mr Dutton said New Zealand was the nation where people could migrate to Australia without a visa, making it an attractive destination for people smugglers.

"It is hard to get this message across to Labor at the moment, that they don't understand the difference between New Zealand and every other country in the world," Mr Dutton said.

Policy change could do harm, commander says

The commander of Australia's border protection regime, Air Vice Marshal Stephen Osborne, has effectively endorsed the Coalition's current policy.

"Operation Sovereign Borders has been very successful now — it's been almost four years without a venture and it's built on a very particular structure," he said.

"If we made any changes to that structure, I would have some concerns and I would just leave it at that."

The Labor Party will debate some changes to its border protection policy at its national conference in July.

One motion is for all unauthorised arrivals to be held in detention for no longer than 90 days, although that would not apply to people in offshore detention.

Shadow Immigration Minister Shayne Neumann again called on the Federal Government to consider the News Zealand deal.

"If the Government was able to negotiate conditions for the US deal, they should be able to negotiate them for any deal with New Zealand," Mr Neumann said.

"Mr Dutton knows that as minister he can prevent any person from any other nation from travelling to, or remove them from, Australia based on character grounds in the Migration Act which contains specific provisions related to people smuggling."