The United States is only option for resettling asylum seekers and Labor will struggle to find somewhere else to take them, Home Affairs Minister Peter Dutton says.
He's cast doubt on Labor's plan to negotiate with new third countries to take asylum seekers stuck on Manus Island and Nauru, as the government is "constantly" trying to find new places to send them.
"There are no prospective cases," Mr Dutton told reporters in Canberra on Wednesday.
"You can go to Europe at the moment and if you can get a deal out of a European nation to take our people from Australia or wherever it might be, let me know about it.
"We have a people smuggling ambassador, we have a whole effort with Operation Sovereign Borders, within DFAT, within my department of Home Affairs.
"We're constantly, in detailed fashion, talking to third countries. The United States is it."
More than 400 asylum seekers have been resettled in the United States, but Mr Dutton says some are refusing to go because they believe they will settle in Australia under a potential Labor government.
Labor leader Bill Shorten has promised to continue the government's policy of turning back asylum-seekers' boats where it is safe to do so, and continue offshore processing.
But he's also promised to negotiate with other countries to resettle asylum-seekers, and do so faster than the current government if he wins the next election.
"Bill Shorten's quite cute with his words about third countries, all he says is 'oh we'll enter into discussions and negotiations' - no kidding," Mr Dutton said.
"We've done that for the last five years and it's not easy."
Labor is trying to amend national security laws to allow for faster medical transfers off Nauru, but Mr Dutton says it will mean the end for offshore processing.
He also confirmed 810 people had been brought to Australia from Nauru for medical treatment, and only a small number had gone back to the island nation.
