Australia will not challenge Wikileaks founder Julian Assange's extradition to the United States and has confidence in the British judicial system, a senior government minister has said.

A British court issued a formal order yesterday for the Australian national to be extradited to the US, where he would face trial for the publication of a trove of secret files relating to the wars in Iraq and Afghanistan.

If convicted, he could face up to 175 years in prison.

"We have confidence in the independence and integrity of the British justice system," Australian Senator Simon Birmingham told the national broadcaster ABC today.

Australia's government was not arguing against the extradition, he said.

"This is a process that will be able to continue to work through that system," said Mr Birmingham, who is Australia's finance minister.

Following the British court's order, Assange's lawyers have until 18 May to make submissions to Britain's interior minister Priti Patel, with whom the final decision about his extradition rests.

Mr Birmingham noted that Assange's right of appeal remained - he can seek appeal to the High Court - and said Australia would continue to provide consular assistance to its jailed citizen.

A coalition of 25 human rights groups, including the American Civil Liberties Union, Human Rights Watch and Reporters Without Borders, has challenged Assange's extradition saying it poses a "grave threat to press freedom both in the United States and abroad".

The Australian has been fighting to avoid extradition for more than a decade, dramatically taking refuge in the Ecuadorian embassy in London in 2012 to avoid extradition to Sweden over sexual assault charges.

He has been held in London's high-security Belmarsh prison since 2019 for skipping bail on the Swedish charges, which were dropped in 2020.

He married a former member of his legal team Stella Moris at the high-security London prison in March.