The file-swapping service Sharman Networks faces a lawsuit brought by the Recording Industry Association of America (RIAA).

Sharman stands accused of helping people pirate copyrighted pop music and films through its software and peer-to-peer network.

The RIAA has already sued three other file-swapping companies, including Morpheus parent StreamCast Networks, Grokster and Kazaa, based in the Netherlands.

On Wednesday, a US federal judge allowed the RIAA to expand its lawsuit to Sharman, which distributes the popular Kazaa software.

Kazaa software sale

The Dutch company Kazaa sold its software to Sharman in February.

Sharman, which is based on a small island in the South Pacific for tax reasons, said it had not yet seen a written order from the court.

The company also said it was confident that its software could survive the legal challenge.

A drawn-out court battle, however, could drain the company's resources.

Until now Kazaa had escaped the wrath of the record industry.