WikiLeaks's main server in France has gone offline, preventing many users from accessing the US diplomatic cables and other documents the site has posted online, a group of Swiss supporters said on Sunday.

The president of the Swiss Pirate Party, which controls the wikileaks.ch web address, said he was in the process of pointing that domain name to a different server, apparently based in Sweden.

"The WikiLeaks server in France seems to have been switched off," Denis Simonet told The Associated Press.

"We're now pointing the domain to another address," he added."That's going to take a few hours."

In the meantime the site is still reachable through the numerical address of its Swedish server, Mr Simonet said.

WikiLeaks has come under attack from governments and private individuals since releasing thousands of classified US State Department messages last month.

On Friday, wikileaks.ch became the site's main access point after the original domain host, EveryDNS.net, stopped accepting traffic to the site's principal address wikileaks.org saying cyber attacks threatened the rest of its network.

Mr Simonet was unable to immediately say why the French server stopped working.

But France's industry minister Eric Besson had warned on Friday that it was unacceptable to host a site that "violates the secret of diplomatic relations".

French web hosting company OVH, which owns the server, did not immediately respond to calls on Sunday.

The company said earlier that it had been hosting WikiLeaks since early Thursday, after a client asked for a "dedicated server with ... protection against attacks".

- AAP