A United Nations human rights panel has ruled in favour of Australian WikiLeaks founder Julian Assange, saying he is being arbitrarily detained at the Ecuadorian embassy London.

Key points: UN says Assange is being arbitrarily detained in London and has a right to compensation

UN says Assange is being arbitrarily detained in London and has a right to compensation Assange's lawyers say the ruling is binding and should allow him to walk free

Assange's lawyers say the ruling is binding and should allow him to walk free UK says decision is not binding and police will arrest him when he leaves the embassy

The United Nations Working Group on Arbitrary Detention confirmed their ruling in a statement tonight, after the BBC and Sweden's Foreign Ministry reported the decision last night.

"The Working Group on Arbitrary Detention considers that the various forms of deprivation of liberty to which Julian Assange has been subjected constitute a form of arbitrary detention," said Seong-Phil Hong, who headed the panel.

But both Britain and Sweden denied that Mr Assange was being deprived of freedom, noting that he had entered the embassy voluntarily.

Mr Assange, 44, has been holed up in the Ecuadorian embassy in London for more than three-and-a-half years.

"I've been detained now, without charge, in this country, the United Kingdom, for five-and-a-half years," he told reporters from the embassy via a video link on Friday.

"Today, that detention, without charge, has been found by the highest organisation in the United Nations that has the jurisdiction for considering the right of detained persons, to be unlawful.

"I consider the outcome in this case to be vindication."

Mr Assange is wanted for questioning in Sweden over sexual assault claims — allegations he has always denied.

The panel found Mr Assange had been deprived of his liberty on three occasions: firstly while in detention in Wandsworth Prison in London, secondly while under house arrest and then finally while in confinement at the Ecuadorian embassy.

It found the detention was arbitrary as Mr Assange "was held in isolation at Wandsworth Prison, and because a lack of diligence by the Swedish Prosecutors Office in its investigations, resulted in his lengthy loss of liberty".

It called on the Swedish and British authorities to "end Mr Assange's deprivation of liberty, respect his physical integrity and freedom of movement, and afford him the right to compensation".

Mr Assange's lawyers said the report meant he should be allowed to freely leave the embassy.

But British authorities have indicated he will be arrested the moment he steps outside so he can be taken to Sweden to face the allegations.

One of Mr Assange's lawyers, Melinda Taylor, said the UN panel's decision was legally binding.

"[The panel] only applies those conventions and legal standards which the United Kingdom and Sweden have explicitly ratified," she said earlier.

"They participated in this process so they should accept its results ... we expect they will fully welcome this decision and this clarity on their international legal obligations."

Another member of the legal team, Jennifer Robinson, added that the lawyers were considering their next move.

"The matter will go before the UN human rights council and we're already considering in light of the statements what our next legal steps will be," she told Lateline.

British Government says ruling changes nothing

The UN Working Group does not have the authority to order the release of a detainee, but it has considered many high-profile cases and its backing carries a moral weight that puts pressure on governments.

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But the UK tonight claimed the ruling had changed nothing.

"This changes nothing. We completely reject any claim that Julian Assange is a victim of arbitrary detention," a British Government spokesman said.

"The UK has already made clear to the UN that we will formally contest the working group's opinion.

"He is, in fact, voluntarily avoiding lawful arrest by choosing to remain in the Ecuadorian embassy.

"An allegation of rape is still outstanding and a European arrest warrant in place, so the UK continues to have a legal obligation to extradite him to Sweden."

Earlier, Mr Assange's legal team said Britain's international reputation was at risk if it ignored the findings.

Sweden's Government "does not agree with the assessment made by the majority of the Working Group", its Foreign Ministry said in a letter to the UN panel, adding that the body did not have the right to "interfere in an ongoing case handled by a Swedish public authority".

Swedish prosecutors said the UN decision had no formal impact on the rape investigation under Swedish law.

Calls for Australia to issue new passport

Greens senator Scott Ludlam, who recently took part in a democracy conference with the WikiLeaks chief, said the decision was "a big deal for Australia" and a challenge to the Turnbull Government.

"Julian Assange is an Australian citizen. The Labor government effectively threw him under a bus and now the challenge is going to be up to Malcolm Turnbull and Julie Bishop as to whether they are going to leave him there," Senator Ludlam said.

"The Australian Government should be lobbying now as they should have been doing for years, he should get his passport back and be free to go."

Senator Ludlam said he had written to Mr Turnbull before his last meeting with US President Barack Obama, asking the Prime Minister to take up the case of Mr Assange.

"We should spare a thought for Chelsea Manning, who is to spend decades behind bars, or Edward Snowden, who is living in exile in Moscow," he said.

"That is what people are worried about, that you end up in Guantanamo Bay not for crimes of terrorism but for acts of publishing. That is what this has been about from the beginning."

Ms Robinson said the legal team had discussed the issue of return of Australian passport back to Mr Assange with Foreign Minister Julie Bishop.

"We did request that his passport be returned to him or that the Australian Government immediately issue him a new passport which they've done in other cases," Ms Robinson said.

"We're hoping Australia will play a positive role given this decision provides a specific mandate to exercise diplomatic protection over an Australian citizen, and given the fact Australia is seeking a seat on the human rights council."

Ms Bishop earlier said she had read the UN report and spoken with Mr Assange's lawyers.

ABC/Reuters