Lawyers for Australia’s recording industry branded the popular Kazaa computer file-swapping network “an engine of copyright piracy to a degree of magnitude never before seen” as they launched a court battle Monday to shut down its activities.

Kazaa’s owners claim the network’s 100 million worldwide users download 3 billion files each month, said lawyer Tony Bannon, who is representing Australia’s six major record labels in a case similar to lawsuits against file-sharing services in the United States.