Wikileaks touts information on Venezuelan president Hugo Chávez's regime

The whistle-blowers' website Wikileaks has marked a change in strategy, calling for media organisations to bid for what it claims is exclusive and confidential information that gives insights into the government of Hugo Chávez, the Venezuelan president.

Wikileaks claims to offer a confidential and high-profile platform for documents that will help expose corruption and unethical practice in government and business - but has, until now, provided access to documentation for free.

But on Tuesday, the site announced that it will auction what it claims are three years of emails from an aide of Chávez to the highest bidder.

Written between 2005 and 2008, the emails purportedly give insights into CIA activities in Venezuela, an incursion by the Colombian Army and how Chávez has managed his government. The winner of the auction will receive the emails under embargo, though the documents will eventually be published on Wikileaks.

The move follows comments earlier this year by one of Wikileaks' coordinators, Julian Assange, who told Wired magazine that the site had turned into a "free-for-all" and that it planned to drop the wiki model.

Despite its popularity, the intensive work of analysing and investigating documents posted on the Wikileaks site is still being carried out by its own staff and a small group of academics. Assange said the site would move to pre-release documents to paying journalists.

In an update to Wired last night, Assange blamed mainstream news organisations for wasting "first-rate source material", because they refused to invest in analysis without what he called "additional incentives".

"The economics are counter-intuitive - temporarily restrict supply to increase uptake," he said. "This is not what we wanted to find, but it has been our solid experience over two years and is a known paradox in economics. Given that Wikileaks needs to restrict supply for a period to increase perceived value to the point that journalists will invest time to produce quality stories, the question arises as to which method should be employed to apportion material to those who are most likely to invest in it."

Earlier this year Wikileaks was backed by news organisations and free speech advocates when a Swiss investment bank issued an injunction to close the site down. The bank eventually dropped the suit after a judge reversed a decision to close the site. Swiss investment bank Julius Baer had objected to documents being posted on Wikileaks that detailed its offshore trading activities.