As many as 100 people suspected of illegally sharing computer game files over the internet are to be sued for copyright infringement, it emerged today.

A London-based law firm said it would launch legal proceedings on behalf of the computer game publisher Topware Interactive after a woman was fined £16,000 for illegally sharing a pinball-themed game over the web.

The woman, who has not been named, was forced to pay £6,000 of damages and £10,000 in costs to Topware after she was found to have uploaded the game Dream Pinball 3D to the internet and distributed it using file-sharing networks.

File-sharing networks have been the bane of the entertainment and media industry for more than a decade. They enable owners of computer games, music and other digital content to 'rip' - or copy - such content to their computer and share it with other users via the internet.

To date the efforts of authorities have focused on those who have shared music, but lawyers said today that the problem also affected the computer game industry, and that fines such as the one issued yesterday would act as a deterrent to file-sharers.

Earlier this year, the Central London County Court separately ruled against four people who were also found to have infringed copyright by sharing computer games illegally.

"Illegal file-sharing is a very serious issue resulting in millions of pounds of losses to copyright owners," said David Gore, a partner at Davenport Lyons, a London-based firm. "As downloading speeds and internet penetration increase, this continues to be a worldwide problem across the media industry which increasingly relies on digital revenues."

"The damages and costs ordered by the court are significant and show that taking direct steps against infringers is an important and effective weapon in the battle against online piracy."

Last month, the music industry announced a three step sanction procedure against illegal file-sharers, in which customers would have their internet connections suspended on the second copyright infringement and cancelled on the third.

The measures were announced as part of a deal agreed between the BPI, which represents record labels in Britain, and internet service providers.

In the past five years, 150 prosecutions have been brought against Britons who have illegally shared music over the internet.