WikiLeaks chief Julian Assange has served the United States an ice-cold slice of revenge by assisting US intelligence leaker Edward Snowden, as well as boosting the flagging profile of his own anti-secrecy website.

The organisation says that it had a legal adviser on the plane Snowden is believed to have taken to Moscow from his bolthole in Hong Kong, and that it helped him seek asylum in Ecuador, in whose London embassy Assange has been staying for a year.

Assange insisted on Monday that his motives were not about vengeance but about defending efforts to challenge what it says is an excessive US culture of secrecy and national security.

"I have personal sympathy with Mr Snowden having lived through a very similar experience," the 41-year-old Australian said in a conference call with journalists.

"But the WikiLeaks organisation more broadly exists to defend the practical rights of whistleblowers to bring their information to the public."

Yet for a man like Assange who believes that US authorities have been trying to hunt him down for the past three years for leaking confidential information, there will be a deep satisfaction in helping Snowden avoid the same foe.

The irony of helping Snowden seek asylum in Ecuador will not be lost on Assange, who sought refuge in the Ecuadoran mission to avoid claims of sexual assault in Sweden that he says are part of a conspiracy to get him to the United States.

Assange said that while WikiLeaks was not actually involved in Snowden's leaks that exposed a huge Internet surveillance programme by the US National Security Agency, it had helped fund his escape from Hong Kong.

He linked his own fate not only with 30-year-old Snowden but with that of Bradley Manning, 25, the US soldier who is being tried on accusations of leaking the documents to WikiLeaks that were behind its first major information dumps in 2010.

WikiLeaks has suffered a series of blows since then, ranging from the rape allegations that led to Sweden seeking Assange's extradition from Britain that year, to the cutting of its funding, and a series of defections by key staff members.

-- 'One of the most important whistleblowers in history' --

For Assange, the Snowden case gets WikiLeaks not just back in the public eye but also boosts its credentials after a hermit-like year sealed in Ecuador's embassy next door to the famed Harrods department store.

The organisation operates in a state of constant wariness. During one encounter with AFP, Assange insisted on conducting a large part of the conversation by writing feverishly on sheets of paper instead of talking, convinced that British and US intelligence services are listening in.

Assange perhaps betrayed his own fears about the United States when just after remarking on Monday that he was in a "very similar situation just three years ago" to Snowden, he added the startling claim that "the kidnapping or incapacitating of Mr Snowden must have been considered" by US authorities.

But WikiLeaks' own secret-busting coups have tailed off since 2010.

Back then it released a slew of US diplomatic cables and documents on the Iraq and Afghanistan conflicts -- but recent releases have been limited to emails by the security contractor Stratfor and a series of 1970s US State Department cables that were mostly already publicly available.

His most recent venture was working on a political song with Puerto Rican band Calle 13.

WikiLeaks however denies it is piggybacking on Snowden's sudden high profile.

Assange insisted that by defending both him and Bradley Manning the organisation is fighting against the "Obama administration's war on whistleblowers."

WikiLeaks' links with Snowden first emerged on June 11 when Assange said he had had "indirect communication with his people" but went no further.

The group's spokesman Kristinn Hrafnsson said that last week that he had personally delivered a message to the Icelandic government recommending that it should grant asylum to Snowden.

Hrafnsson is Icelandic and WikiLeaks was previously based there.

Hrafnsson told the BBC that WikiLeaks was helping Snowden because he is "one of the most important whistleblowers in history."

But WikiLeaks appeared to have jumped the gun on one aspect of the case, when in a press release on Sunday it quoted renowned Spanish former human rights judge Baltasar Garzon as saying he was "interested in preserving Mr Snowden's rights."

Garzon clarified that on Monday to say he was still waiting to talk to the American to get more information, adding that "as of today I do not represent Mr Snowden's interests".