"Robust", "contentious" and "hostile" is how a weekend phone call between Prime Minister Malcolm Turnbull and US President Donald Trump has been described.

It is a stark contrast to the congenial description of the conversation both governments gave immediately after.

The flashpoint of the phone call was the refugee deal struck between Mr Turnbull and former US president Barack Obama, according to the Washington Post journalist who broke the story, Philip Rucker.

Timeline: Conflicting claims 10:00am (AEDT): White House says Donald Trump considering deal

10:00am (AEDT): White House says Donald Trump considering deal 11:00am: State Department says deal is on

11:00am: State Department says deal is on 2:00pm: US Embassy says deal is on

2:00pm: US Embassy says deal is on 3:00pm: Trump tweets he will study deal

"Trump objected to that — he feels like that's a bad deal," Rucker told ABC News 24.

Mr Trump told Mr Turnbull it was "the worst deal ever", and reportedly accused the Prime Minister of seeking to export the "next Boston bombers" to the US.

"That is a reference, of course, to the Boston Marathon terrorist attack a few years ago," Rucker said.

"He thinks the deal hurts him politically at home in the United States, and he feels like, I think most importantly, that this would be a threat to national security and he told the Prime Minister as much."

Mr Trump reportedly told Mr Turnbull "I don't want these people", while discussing the resettlement deal.

Donald Trump on the phone to Malcolm Turnbull ( AP: Alex Brandon )

Rucker said the phone call — which Mr Trump reportedly labelled "the worst by far" of a clutch of calls to world leaders — was described to him as "contentious and, at time, hostile".

"[Mr Trump] spoke with a total of five foreign leaders ... and told the Prime Minister of Australia that, you know, of all five of those calls, including the call to [Russian President Vladimir] Putin, that the Australia call was the most difficult for him.

"'It was the worst by far' — that's Trump's language.

"He was not pleased with the call — it did not last the full hour that was anticipated and it ended after 25 minutes."

'He didn't let diplomatic niceties get in the way'

Rucker said the phone call was further evidence Mr Trump was "not a natural diplomat".

"He is not a politician — he has a career in real estate, in business and deal-making, and he ran for President as somebody who was going to disrupt the world order," Rucker said.

"He was going to make changes and he was going to blow up the system — literally — and disrupt what he sees as a world order that is failing the world and making it more dangerous and less safe.

"He doesn't really care so much that Australia is an ally over many, many years — what he cares about is the refugee policy that he views as dangerous for the United States.

"He didn't let diplomatic niceties get in the way of how he felt about that refugee policy."

Sorry, this video has expired Malcolm Turnbull remained tight lipped on the "worst conversation".

Refugee deal in doubt amid conflicting claims

Rucker said it was unusual for details of conversations between leaders to be leaked — but that this story had come from senior US officials.

"I don't know why necessarily these have been leaked out, but we have a lot of sources within the US Government," he said.

"My colleague Greg Miller and I heard about this conversation from senior US officials who have been briefed on some of the exact quotations from the conversation, and shared that information with us.

"It was a pretty extraordinary call — the tone and substance of it certainly differs from the relatively sanitised account that came out of both governments on Saturday (local time)."

As for the refugee deal that reportedly sparked the "hostility"? It remains in doubt.

The White House said Mr Trump was still evaluating the deal, while the State Department said refugees would come to US in accordance with the President's recent executive order.

Mr Trump also tweeted that he was personally "studying" the deal, which he described as "dumb".

"President Trump told the Prime Minister that it was his intention — quote 'my intention to honour the agreement that had been reached previously regarding the refugees'," Rucker said.

"Now, that seems to leave Trump a little bit of wriggle room to get out of that deal if he so chooses down the road.

"But nevertheless he gave the Prime Minister his assurances that he intended to stick with the deal."