US Attorney-General William Barr has been tasked with examining the events that prompted the FBI probe, and Mr Trump wants Australia's role examined.

The president said on Friday he has declassified "potentially millions of pages" of intelligence documents related to surveillance activities on his campaign so Mr Barr can analyse them.

"He can look and I hope he looks at the UK and I hope he looks at Australia and I hope he looks at Ukraine," Mr Trump told reporters.

Foreign Minister Marise Payne says Australia has not been asked to be part of Mr Barr's investigation.

"We have not been asked to participate. We would, of course, consider such a request were it to be made," she told ABC Radio National on Monday.

The minister has also followed Prime Minister Scott Morrison's lead by not commenting on what the investigation may cover.

"We don't intend to engage in a public commentary that might entail any risk that we're seen to prejudice the ongoing examination of these matters in the US."

The move has been denounced by some members of US Congress who predicted trust between the Five Eyes intelligence sharing nations - the US, Australia, UK, Canada and New Zealand - could be eroded.

The FBI probe led to Bob Mueller being appointed as US Special Counsel to investigate links between the Trump campaign and Russia.

His report pointed to a 2016 meeting between in a London bar between then Trump campaign aide George Papadopoulos and Australian's then high commissioner to the UK Alexander Downer.

Mr Downer claimed Mr Papadopoulos told him at the bar Russia had damaging material on Trump's presidential rival Hillary Clinton.

The information was forwarded to Canberra and then passed on to US intelligence services and the FBI.

Mr Papadopoulos in return claimed Mr Downer spied on him during the bar meeting, a charge Mr Downer rejects.

Papadopoulos later pleading guilty to lying to the FBI. He was sentenced to 14 days' jail.

Australian Associated Press