Prime Minister Scott Morrison has defended Donald Trump over the contentious withdrawal of US troops from northern Syria as the US President is accused of leaving Kurdish allies exposed to an imminent attack from Turkish forces.

Mr Morrison said Australia urged restraint on all sides in the Middle East and believed Mr Trump took the same approach, raising no doubts about whether the US could be trusted as an ally.

Prime Minister Scott Morrison said Mr Trump had shown restraint on the subject of Iran in their talks in the White House last month. Credit:Getty

The Prime Minister said Mr Trump had outlined his intention to withdraw troops from Syria, Afghanistan and Iraq one year ago and was now acting on that message.

"I think it would be wrong to not draw an element of consistency between those statements almost a year ago and the action the United States has been taking since, including most recently," he said.