The US government is proposing a series of tough new measures to combat unsolicited email.

The US Senate Commerce Committee yesterday passed a beefed up proposal to stamp out spam, promising that the legislation would be strengthened further by the time it comes to a full vote.

By adding to a measure known as 'Can-Spam', it gives greater authority to internet service providers and federal authorities, such as the Federal Trade Commission (FTC).

They will be able to sue spammers who use software to harvest email addresses from the internet, as well as those who forge or spoof email headers or do not allow recipients to unsubscribe.

Violators could face up to one year in prison and fines of up to $1m.

Two senators on the US Judiciary Committee have also introduced an even tougher act that could send spammers to jail.

If passed, a first offence under the Criminal Spam Act would be punishable by up to three years in prison. But those who repeatedly send spam could face imprisonment for up to five years and fines of up to $25,000 a day.

Both the Commerce Committee measures were passed by voice vote with little debate, reflecting the general feeling on Capitol Hill that new laws are needed to stop the electronic deluge of pornography, get-rich-quick schemes and quack miracle cures.

The Committee also gave the FTC, which blames the worst varieties of spam on overseas spammers, the greater powers that it demanded to track down offenders.

It will relax disclosure laws and allow the agency to build better cooperation with other countries to track down spammers who operate across international borders.