The UK is taking part in a worldwide operation to fight internet fraud.
The Office of Fair Trading, and Highland, Essex, Milton Keynes and Sutton trading standards authorities are working on an international law enforcement project that targets phoney get-rich-quick schemes on the net.
The project, called GetRichQuick.Con, involves 150 organisations in 28 countries and has so far collated information for the US's Federal Trade Commission (FTC) on more than 1600 suspect websites.
The participating UK consumer groups found nearly 100 potentially misleading sites, including a number based in the UK.
John Bridgeman, director general of the Office of Fair Trading, said: "People should be very wary of claims that large amounts of money can be earned for little or no effort or in an extremely short timescale. If something sounds too good to be true, then it probably is."
Suspect sites are being informed that they are under surveillance, with links to the participating consumer groups' sites, and warned that the strong arm of the law will collar those that continue to make misleading claims.
The suspect sites will continue to be monitored and could be shut down if they do not change their claims to comply with the law.
Jodie Bernstein, director of the FTC's bureau of consumer protection, said: "Internet con artists are bad actors without borders. We want them to know that the borderless internet marketplace is not a free zone."
The sweep, conducted last month, targeted bogus work-at-home offers, business opportunity scams, illegal lotteries and other sites offering easy riches.
Partners were recruited through email, and a step-by-step manual for conducting the surf and collecting evidence was posted on a password-protected website.
Evidence about suspected sites was submitted into a database administered by the FTC in Washington.
Christine Gregoire, Washington Attorney General, said: "We intend to develop the tools and co-operative agreements needed to help protect consumers."
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