A judge has granted a preliminary injunction against the internet file-swapping service Madster, saying it "contributes to copyright infringement on a massive scale".

The order, issued by a court in Chicago, is a victory for record companies which claim that Madster causes as many problems with copyright as Napster did before it.

More than two dozen record and media companies are taking legal action against the service.

"At issue is a service whose very raison d'etre appears to be the facilitation of and contribution to copyright infringement on a massive scale," said Chief Judge Marvin Aspen before granting the preliminary injunction.

Renamed

He gave the companies suing Madster until next week to propose wording for an injunction that would end their copyright infringement.

Madster, formerly called Aimster, was renamed earlier this year after a dispute with internet giants America Online, which claimed the name was too similar to that of its online Instant Messenger service, known as AIM.

Madster began as a free service that allows users to trade music and other files over the internet. It now operates a subscription service that gives users access to extra files for a small fee.

Napster is now facing liquidation

Founder Johnny Deep said he had not seen the opinion of the judge in yesterday's hearing, but he did not think think there was a lot of copyright material shared on Madster.

However, the Recording Industry Of America (RIAA) said all of the service's arguments had been rejected by Aspen.

"This unequivocal ruling underscores that companies and individuals will not be permitted to build a business on music they do not own and will be held responsible for their actions," said a RIAA spokeswoman.

The move comes just a day after a judge blocked the sale of the file-swapping site Napster to music label Bertelsmann.

The German giants had agreed to pay $9m to Napster creditors to buy the pioneering internet company, which until last year provided its users with software to swap copyrighted songs for free.

The company, which was founded by student Shawn Fanning, is now expected to close down its operations and sack its remaining staff.