BERLIN – A war of words erupted on Thursday between WikiLeaks and a disgruntled former employee who published a tell-all book dishing the dirt on the whistle-blowing website and its founder Julian Assange.

"Inside WikiLeaks" is billed as an account of Daniel Domscheit-Berg's time as programmer and media spokesman for what his book, due for release in 16 countries from Friday, calls "the world's most dangerous website."

It says the "chaotic" WikiLeaks cannot protect its sources, accuses the "power-obsessed" Assange of betraying the website's founding ideals and says that Assange was worryingly secretive about WikiLeaks' finances.

He calls the 39-year-old Australian "brilliant" but "paranoid" but also a "megalomaniac" whose personal hygiene and eating habits suggest he was "brought up more by wolves rather than humans."

Domscheit-Berg also said that when he left along with others in September he took important software vital to the security of the WikiLeaks site and blocked access by Assange to some 3,500 documents.

"Children shouldn't play with guns," he says in the book. "We will only return the material to Julian if and when he can prove that he can store the material securely and handle it carefully and responsibly."

Assange also has links with "dubious" people including Israel Shamir, a "famous Holocaust denier and anti-Semite" from Sweden, Domscheit-Berg told reporters as he presented his book in Berlin.

"This is alarming, to put it mildly. I was very shocked," he said.

WikiLeaks said it has launched legal action, playing down Domscheit-Berg's importance within the organisation and countering that his claims were based on "limited information or malicious falsifications."

"In the book Domscheit-Berg confesses to various acts of sabotage against the organisation," WikiLeaks spokesman Kristinn Hrafnsson said in a statement emailed to AFP.

"It should be noted that Domscheit-Berg's roles within WikiLeaks were limited and started to diminish almost a year ago as his integrity and stability were questioned."

Domscheit-Berg, along with others, left WikiLeaks in September complaining that Assange was autocratic and that the organisation, ironically for a group on a crusade for openness, was becoming excessively secretive.

"When Julian decided to misrepresent the situation around my departure publicly, and started to discredit me with half-truths and lies, I decided to get some of the facts straight," Domscheit-Berg told AFP.

Founded in 2006, WikiLeaks caused a storm last year with major document leaks on the wars in Iraq and Afghanistan, as well as publishing US diplomatic cables that have caused Washington and others considerable embarrassment.

The leaks have earned Assange and WikiLeaks massive public attention and plenty of enemies.

Assange is currently in London fighting extradition to Sweden over allegations of rape and molestation following his arrest by British police in December, a case he says is politically motivated.

In the book, Domscheit-Berg also has a dig at Assange's attitude to women, recounting how he used to "boast" about how many children he had fathered around the world, and even alleges that Assange abused Domscheit-Berg's cat.

"Julian's main criterion for a woman was simple. She had to be young. Preferably younger than 22 ... 'She has to be aware of her role as a woman,' he used to say," according to the book.

"We were once best friends, Julian and I, or at least something like that," he says in the German-language version of the book.

"Sometimes I hate him so much that I get scared that I might get violent with him if he ever crossed my path again. But then I think he might need my help."