Whistleblower website WikiLeaks has been losing $620,000 a week since it began publishing confidential US cables, founder of the site Julian Assange said.

Mr Assange told Swiss newspapers Tribune de Geneve and 24 Heures personal pressure placed on him "reinforces my determination".

"But from a financial point of view, it's another matter," he said.

"We have been losing more than 600,000 francs ($620,053) a week since the start of the publication of the diplomatic cables.

"To continue our business, we would need to find a way or other to get this money back."

There was no explanation of why Wikileaks was losing money with the publication, but several banks or payment systems have terminated business with the website in recent weeks.

The Australian is on bail in Britain facing extradition proceedings to Sweden on charges of sexual assault.

The date of his trial is to be fixed during a hearing on Tuesday (local time) in London.

Media reports suggest US prosecutors are also trying to build a case against him on the grounds that he encouraged a US soldier, Bradley Manning, to steal cables from a government computer and pass them to WikiLeaks.

Mr Assange had also acknowledged during a December interview to Britain's Sunday Times that financial difficulties had pushed him to sign more than $1.55 million in deals for his autobiography.

He denied having already received this sum.

"Contrary to what has been said, I have not received 1.1 million pounds to write my autobiography. I would get 1.1 million pounds in a couple of years' time if my book became a success," he told the Swiss newspapers.

Mr Assange denied rumours that he had asked for asylum in Switzerland and said he is still "in the process of deciding which country would be most appropriate in terms of security for me and my team".

"Switzerland remains a possibility," he said, adding that "we are not excluding Australia either".

- AFP