SAN FRANCISCO - NEARLY 95 per cent of the e-mail sent in 2007 has been 'spam', junk advertising loathed by its recipients, according to a report released by a United States Web security firm.

The amount of junk e-mail has skyrocketed despite a 2004 US Can-spam Act that placed restrictions on sending unwanted messages and sanctioned penalties for 'spammers', according to California-based Barracuda Networks.

Junk messages made up an estimated 70 per cent of e-mail the year the act was passed, the Barracuda report indicates on Wednesday.

'The spam war is a continuous battle between spammers and security vendors,' said Barracuda chief executive Dean Drako.

'Security vendors now require 24-by-7 defence operations to continuously monitor the Internet for new spam trends and distribute new defensive solutions immediately.'

Barracuda said it based its findings on analysis of more than a billion e-mail messages received daily by its approximately 50,000 customers worldwide.

Spammers cunningly hide their identities by routing e-mails through other people's websites, blogs or computers, according to Barracuda. -- AFP