Donald Trump urged the Australian prime minister to help with a US investigation which may have brought political benefits to the president.

The US president used a phone call to urge Scott Morrison, the Australian leader, to help William Barr, the US attorney general, on an investigation he was running, the New York Times reported.

The investigation was looking into the origins of the Russian election meddling probe, which long hung over the Trump presidency.

Mr Trump has argued the investigation, which looked at links between the Trump campaign and Russia, was launched inappropriately by the Barack Obama administration before the 2016 election.

The Australian government on Tuesday said Mr Morrison had agreed to help.

"The Australian government has always been ready to assist and cooperate with efforts that help shed further light on the matters under investigation," Mr Morrison's office said in a statement.

"The PM confirmed this readiness once again in conversation with the president," the statement said. It did not say when the call took place.