US record companies have launched a Napster-style legal assault on a new firm that allows consumers to download the latest tracks from hit artists such as Christina Aguilera and the Red Hot Chili Peppers for free.

Four major companies - BMG, Sony, Universal and Warner - have taken the unusual step of launching action against the internet companies that give access to the offending website as part of ongoing efforts to combat music piracy on the web.

Listen4ever.com is registered in China and, like Napster, allows web users to download songs from a central location. The copyright infringement suit, filed in Manhattan over the weekend, alleges the site is "even more egregious" than Napster.

The site features tracks from thousands of artists, including Christina Aguilera, Bruce Springsteen, the Red Hot Chili Peppers, Eric Clapton and Whitney Houston, that users can download for nothing and then copy to CD.

The record companies claim that although they have been unable to determine who owns the site, the internet service providers should stop their users from accessing it because it is clearly aimed at the US and breaches copyright law, despite being registered in China.

Record companies, hit by falling sales, are becoming increasingly desperate to find a solution to the growing problem of internet piracy. Although they succeeded in crippling Napster through a series of lawsuits, a host of similar sites have sprung up in its place.

Meanwhile, the record companies' own attempts at launching legal music download networks such as PressPlay and MusicNet have proved less than popular, partly because of the number of free alternatives and partly because they only offer a limited selection of music.

Listen4ever.com is a relatively easy target because, like Napster, its songs are hosted on a central computer.

Far harder to close down are a new generation of music-swapping services, such as Kazaa and Grokster, which allow users to share tracks stored on their own computers.

These "peer-to-peer" services are already attracting up to 3.5m downloads a week and the British Phonographic Industry fears the scale of the piracy will be far great than caused by Napster.

Unlike Napster, which stored a library of tens of thousands of tracks in a central computer, the peer-to-peer service relies on CD collections stored on home computers.

The software allows anyone signed up to the service to have a look at everyone else's collections, causing a nightmare for copyright lawyers accustomed to tackling corporate theft.

Some 100 million computer owners are registered for the peer-to-peer use, dwarfing Napster, which attracted 20 million users at its peak.

The Recording Industry Assocation of America estimates that record companies have already lost 5% of their worldwide revenue over the past two years due to the rising popularity of illegal downloads.

In the UK a recent report from the British Phonographic Industry showed that single sales were down 15% in the last quarter from a year ago.