A multi-party delegation of six Australian politicians will travel to the United States to push for an end to the pursuit of WikiLeaks founder Julian Assange.

The US has pushed to extradite Julian Assange, who is an Australian citizen, after his website WikiLeaks published thousands of US documents in 2010, which included a cache of military and diplomatic files, some of which were classified.

Mr Assange has been detained in in Britain’s Belmarsh Prison for the last four years and is in the midst of appealing the United Kingdom’s decision to agree to US extradition.

The cross-party group, including former deputy prime minister Barnaby Joyce, revealed their intention to the press in Canberra on Tuesday, September 5.

The group of MPs told reporters gathered at Parliament House in the nation’s capital that they have timed their trip for maximum impact as Australian Prime Minister Anthony Albanese prepares to visit the White House in October.

Member for Kooyong Monique Ryan told the Australian Broadcasting Corporation (ABC) that the cross-party delegation represents a large group of MPs who feel “really, really strongly about the importance of securing Mr Assange’s freedom”.

Dr Ryan said: “What we will be asking the US to do is to demonstrate their commitment to the First Amendment.”

Greg Barns, human rights lawyer and campaign adviser for Mr Assange, Greg Barns said the majority of Australians believe the US pursuit of the WikiLeaks founder should come to an end.

“That can only happen if the US Department of Justice drops its extradition bid at once,” he said.

Mr Assange’s brother Gabriel Shipton added that Australians had had a “gutful”.

Mr Shipton said: “The vast majority of Australians can’t understand why the US continues to act in a way that keeps Julian locked up in one of the worst prisons in the UK.

“Even Australians who didn’t support Julian’s actions believe he has suffered enough and should be set free immediately.

The delegation will include former Nationals leader Barnaby Joyce, Liberal senator Alex Antic, independent MP Monique Ryan, Labor MP Tony Zappia and Greens senators David Shoebridge and Peter Whish-Wilson.