WikiLeaks founder Julian Assange could be extradited to the US in less than a week, and if Australia fails to act, he may die in an undisclosed American prison, his advocates say.

The House of Representatives passed a motion on Wednesday which urged the US and UK governments to allow Assange to return to Australia.

More than two-thirds of MPs backed the move, with Labor, crossbenchers and Liberal Bridget Archer all in favour – alongside Prime Minister Anthony Albanese.

While independent MP Andrew Wilkie lauded the occasion as a “remarkable day in the House of Representatives”, the government needs to keep pushing, he said.

“Yesterday, something changed for the better,” he told reporters on Thursday.

“I’m hoping that yesterday was more than a vote … that it was a signal the government will ramp up its efforts.”

Wilkie has urged the government to raise Assange’s extradition with the US ambassador, the State Department, the Justice Department and the White House so the US government drops its case against the Australian.

Assange will front the High Court in London on Tuesday in what could be the final bid to prevent his extradition after more than a decade spent evading the Americans.

The 52-year-old lived in London’s Ecuadorian embassy under political asylum from 2012 to 2019 and has been in a high-security English prison for more than four years.

According to his brother Gabriel Shipton, Assange’s health is quickly deteriorating.

“If his appeal is rejected, that means all his ties to his family – his lifeline to keeping him alive inside prison – will be cut off and he’ll be lost in a horrific prison system,” Shipton told reporters in Canberra.

“We’re really living in fear that this extradition is becoming imminent, and we could lose Julian forever.”

Assange is facing 17 espionage charges after WikiLeaks published a haul of classified documents about US operations in the Iraq and Afghanistan wars more than a decade ago.

Independent MP and former journalist Zoe Daniel directly addressed US President Joe Biden as she expressed support for Assange.

“Julian is being punished for telling the truth, and we live in a world where truth is in short supply,” she said.

Though many members of the coalition opposed the motion, some – including Opposition Leader Peter Dutton – have previously backed Assange .

Bipartisan support largely failed due to sticking points around language such as the motion’s description of the leaks as “shocking evidence of misconduct by the USA”.

“I don’t think that diminishes the support we have seen expressed yesterday … (nor) the public statements that have been made across political lines,” Ms Archer said.

“Everybody wants to see this matter brought to a close even if they’re going to ultimately argue about some words on the floor of the parliament.”

– AAP