New York: The White House has appeared to back away from a commitment to take more than a thousand refugees from Australia's offshore detention centres, saying President Donald Trump was "still considering" the plan on Wednesday.

Prime Minister Malcolm Turnbull told the National Press Club in Canberra Mr Trump's assurances on Sunday that he would honour the deal remained in tact, despite a White House official telling the ABC the new president was "still considering whether to actually go ahead" with the plan. The official reportedly said that if it did happened it would "be only because of the longstanding relationship with Australia".

The clarification came after press secretary Sean Spicer used the daily White House press briefing to confirm the deal struck by the Obama administration would go forward, confirming for the first time that the US would subject 1250 people held on Manus Island and Nauru to "extreme vetting" for potential resettlement in the United States.

"Part of the deal is they have to be vetted in the same manner that we are doing now. There will be extreme vetting applied to all of them," Mr Spicer said in the briefing.