Experts said today a new version of the Melissa virus has emerged.
Melissa.W is a form of Melissa.A which crashed computer networks in March 1999 by clogging up e-mail systems.
It comes as part of a file named "Anniv.doc" in Microsoft Word 2001 for Macintosh format.
"This virus could become very widespread rapidly," F-Secure Corporation, a Finnish-based software company, said in The Sydney Morning Herald.
"The format of the infected file has changed. This is problematic, as several anti-virus programmes are still unable to handle this new file format, but the file and the virus is fully functional under both Macintosh and Windows versions of Microsoft Office."
Symantec, an anti-virus software group in Cupertino, California, said the new Melissa virus spreads via e-mail with the subject line displaying, "Important Message From (user name)" and text which reads "Here is that document you asked for ... don't show anyone else;-)."
It said Melissa will send the virus to the first 50 people in a user's Microsoft Outlook address book and infect each subsequent document that is opened.
PA