Consumers who swap music online tend to increase music purchases rather than reduce them, according to a study released by Jupiter a New York-based Internet commerce analysis firm.

The study shows use of the popular but controversial MP3 music-swapping service Napster to be an indicator of increasing sales, said Aram Sinnreich, an analyst with Jupiter.

"Screening for Napster users in general, they were 45 percent more likely to increase their music purchases than non-Napster using music fans," he said.

"It behooves the recording industry to stop litigating immediately. If they just turn a blind eye, they would increase their sales."

The Recording Industry Artists Association (RIAA) launched a series of lawsuits against companies distributing MP3-format music online, including Napster, alleging the service amounts to the promotion of copyright infringement and that it hurts music sales.

The RIAA has also sued and most recently the search engine and file-sharing program site Scour for copyright infringement.

A Jupiter spokeswoman said the study had not been commissioned by either Napster or the RIAA. The study was timed for release before Jupiter's Plug.In conference, to be held today and tomorrow in New York.

The conference, sponsored partly by Internet music companies, will feature Richard Parsons, the president of Time Warner, Rob Glaser, chairman and chief executive officer of Real Networks and rap artist Mike D of the recording group Beastie Boys.