The battle of file swapping networks seems to be repeating itself today as a host of music companies sue Kazaa's owners Sharman Networks over copyright infringement.

Music labels including EMI, Warner, Sony BMG and Universal have clubbed together to fight what it is saying is “an engine of copyright piracy to a degree of magnitude never before seen”

The case is being held in Australia because Sharman Networks is based in Australia, but registered in the Pacific Island state of Vanuatu.

Sharman Networks, via Kazaa is reported to be swapping 3 billion files a month between its 100 million users. However Sharman Networks is defending this allegation by denying that it knows of the files its customers are swapping.

This is not the first time that Kazaa has been in the courts. In 2003 a court in the Netherlands found it not guilty of breaking copyright infringement when it decided the software had a valid legal use.

Sharman opens its defence on Tuesday.