Trump has asked advisors if it is possible for the US to acquire Greenland
Trump has asked advisors if it is possible for the US to acquire Greenland AFP / SAUL LOEB

Australia's opposition demanded the transcript of a call between Prime Minister Scott Morrison and Donald Trump be released Wednesday, as controversy mounted over a politically fraught offer to help the US president.

Amid concern that Australia may be co-opted into helping Trump tarnish his domestic political rivals, opposition leader Anthony Albanese demanded to know what information Canberra had turned over to Washington.

Morrison's office admitted Tuesday that the prime minister personally offered to "assist and cooperate" with an investigation that the US president hopes will discredit findings that Russia helped his 2016 election campaign.

Australia is a long-standing security ally of the United States and close relations usually enjoy strong bipartisan support Down Under. But that consensus has been tested since Trump took office.

"The prime minister needs to explain exactly what went on here. He needs to release any transcript and information which is out there," Albanese said.

"This is quite extraordinary," he added. "The prime minister needs to make a full statement."

Trump and his media allies have long promoted theories that FBI and other investigations into Russia's role in the 2016 election were prompted by a pro-Democrat "deep state".

Those largely unsubstantiated allegations have ensnared allies in Britain, Italy and Australia.

One of the catalysts for the FBI probe was a Trump campaign official admitting to the then Australian ambassador in London that the Russians had "dirt" on Trump's rival Hillary Clinton.

The campaign official, George Papadopoulos, was jailed for lying to the FBI. But his allegation that the ambassador -- former conservative foreign minister Alexander Downer -- was one of several "spies" sent to entrap him has gained currency in Trump's White House.

Downer reported the conversation to top officials in Canberra and ultimately to US authorities.

Australia's current foreign minister Marise Payne on Wednesday refused to say what "material and information", if any, was exchanged with Trump.

"It's not my practice to comment on the use of intelligence to secure material," she told ABC radio.

But she also sought to quell concerns that her government acted inappropriately -- saying it would cooperate with Trump only "as far as we can and as far as is appropriate".