WikiLeaks founder Julian Assange gestures from the balcony of Ecuador's Embassy in central London (Reuters)

WikiLeaks founder Julian Assange is on a journey from champion of freedom to cult leader, says one of his former high profile supporters.

Heiress Jemima Khan said that Assange is increasingly like Scientology founder L Ron Hubbard, due to his despotic and murky management of WikiLeaks.

"The problem is that WikiLeaks - whose mission statement was 'to produce a more just society based upon truth' - has been guilty of the same obfuscation and misinformation as those it sought to expose, while its supporters are expected to follow, unquestioningly, in blinkered, cultish devotion," Kahn wrote on the New Statesman.

Khan spoke out against Assange, who is wanted for questioning by police in Sweden over sex assault and rape allegations, after she received criticisms from the 41-year-old Australian over her involvement in the production of a documentary feature he perceived as "anti-WikiLeaks".

"I have seen flashes of Assange's charm, brilliance and insightfulness - but I have also seen how instantaneous rock-star status has the power to make even the most clear-headed idealist feel that they are above the law and exempt from criticism," Khan wrote.

After having lost a legal battle to avoid extradition in Sweden Assange jumped bail and took sanctuary at the Ecuadorian embassy in London, in June last year.

Kahn was amid the group of Assange's supporters that put up £200,000 as surety for him to be granted bail and invariably lost the money, as he sought asylum in the Knightsbridge Embassy.

"I don't regret putting up bail money for Assange but I did it so that he would be released while awaiting trial, not so that he could avoid answering to the allegations," Khan wrote.

"It may well be that the serious allegations of sexual assault and rape are not substantiated in court, but I have come to the conclusion that these are all matters for Swedish due process and that Assange is undermining both himself and his own transparency agenda ... by making his refusal to answer questions," she added.

Khan is an executive producer of a documentary by Alex Gibney titled: WikiLeaks, We Steal Secrets.

A tweet by WikiLeaks described the movie as "an unethical and biased title in the context of pending criminal trials."

Khan concluded warning Assange against throwing away all the good he has done through WikiLeaks' revelations.

"It would be a tragedy if a man who has done so much good were to end up tolerating only disciples and unwavering devotion, more like an Australian L. Ron Hubbard."