Microsoft has initiated 15 lawsuits against alleged email spammers in the United States and Britain.

The defendants are accused of flooding Microsoft's computer systems and its customers with more than two billion deceptive, unsolicited emails.

The company said the lawsuits addressed some of the most misleading, deceptive and offensive spam email received by Microsoft customers.

Thirteen of the lawsuits were filed in Washington state, which recently passed tough anti-spam laws, while the other two were filed in Britain.

"Spam knows no borders. It is an issue that requires global co-ordination so that industry and government have the maximum ability to protect consumers," Microsoft lawyer Mr Brad Smith said.

Spam accounts for half of all email traffic, according to some estimates.

Huge volumes of unsolicited messages clog up email in-boxes and can dramatically slow down computer networks.

Many spam messages advertise porn websites, causing offence as well as inconvenience to individual email users.

Launching the lawsuits, Microsoft cited Washington's strong anti-spam law, which allows internet service providers to take action against spammers. - (AP)