The mother of Julian Assange has pleaded with Prime Minister Malcolm Turnbull to secure her son's release, six years to the day after he was arrested.

Christine Assange made phone calls to the PM's and Foreign Minister Julie Bishop's offices on Wednesday to ask for their help in releasing the WikiLeaks founder from the Ecuadorian embassy in London, six years after he was arrested in the UK on December 7, 2010.

"Today he has been detained six years without charge," Ms Assange told AAP on Wednesday. "It's time for the Australian government to stand up for my son's human and legal rights."

The request comes a week after Assange, 45, renewed his plea to be freed from the embassy, where he has lived for more than four years, after a United Nations panel confirmed that he is a victim of arbitrary detention.

A request by the UK government to review the case was recently rejected by the UN Working Group on Arbitrary Detention after it found in February that Britain and Sweden had "arbitrarily detained" Assange.

The panel said he should be freed and entitled to compensation.

"I have called on the Australian prime minister and my son's foreign minister to stand up and demand that UK and Sweden obey the ruling," Ms Assange said.

Assange, who enraged Washington by publishing a flood of secret US diplomatic cables, sought asylum at the embassy fearing that, if extradited to Sweden, he could be sent on to the United States and face a long prison term there for leaking US secrets.

Ms Assange said the inaction of both the coalition and Labor governments is a result of putting their careers ahead of duty.

"As an Australian citizen I find the silence from both parties indicates a complete lack of sovereignty in regards to the US in that they're not willing to stand up for truth or justice or human rights."

However, Ms Bishop's office told AAP the Australian government "has offered consular assistance (to Assange) on numerous occasions, which has either been refused or we have not received a response".

Mr Turnbull's office was contacted for comment.