The lawsuit, filed last week in a federal court in Brooklyn, accuses New Yorker Thomas Simon of copycatting in Second Life, an Internet universe with more than 10 million registered members, the New York Post reported.

Creating virtual identities known as avatars, members spend an average of more than US$1 million (S$1 million) a day in real money to buy food, clothes, shelter and other items.

The vendors suing Mr Simon say he violated copyright and trademark laws by duplicating their products. The lawsuit seeks damages equal to three times their lost profits, without specifying an amount.

'This is not a joke,' said their lawyer, Frank Tanney. 'This hurts them.' Mr Simon, who goes by the name Rase Kenzo in Second Life, denied any wrongdoing.

'It's a video game,' said Mr Simon, 36. 'I didn't know you could sue anyone over it.' Claims of product cloning in Second Life have already spawned at least one other lawsuit, filed in July in a federal court in Tampa, Florida.

Members also have sued the online world's creator, San Francisco-based Linden Lab, over alleged seizures of their virtual property.

Company representatives did not immediately respond to telephone and e-mail messages early Sunday. -- AP