The government's confusion over the US refugee “deal" is creating further anxiety and uncertainty for people who have already suffered for far too long, Greens Immigration spokesperson Nick McKim says.

"While the government argues with itself over whether or not this is a people swap, there are men, women and children suffering in Australia's inhumane detention centres due to the ongoing uncertainty," Senator McKim said.

"This 'deal' was apparently signed more than three months ago, yet not a single person has been resettled in the United States."

Malcolm Turnbull should end the uncertainty and confusion over the US refugee "deal" and bring the people to Australia, Greens Immigration spokesperson Nick McKim says.

"It is now clear that the US deal relies on an unhinged, dishonest President," Senator McKim said.

"People should be very concerned about what Mr Turnbull is prepared to do to get this deal done."

"As we now know, the deal does not commit the US to accept a single person."

The Department of Immigration and Border Protection has confirmed that the US is not obliged to accept a particular number of refugees, or indeed any, under the terms of its "deal" with the Australian government.

"We  learned today that the agreement provides no certainty whatsoever for the men, women and children that Australia has detained on Manus Island and Nauru," Greens Immigration spokesperson Senator Nick McKim said.

The federal government's must end its secrecy over its "deal" with the United States to resettle refugees from Manus Island and Nauru.

"The government's lack of information about this arrangement is causing significant anxiety to people detained on Manus Island and Nauru," Greens Immigration spokesperson Nick McKim said.

"Prime Minister Malcolm Turnbull needs to reveal how many people will be resettled in the United States, under what conditions, and how long will it take."

The federal government's announcement of a deal with the United States is an admission that offshore detention has to end, but still leaves people on Manus Island and Nauru facing an uncertain future.

"After three years, the government has finally admitted that offshore detention is a dead-end, but has offered no certainty that people will not be left behind to languish on Manus Island and Nauru," Greens Immigration spokesperson Nick McKim said.