The Internet Fraud Complaint Center's annual report said it logged 49,711 complaints ranging from fraud to computer intrusions, hacking and child pornography.

The centre, which is a partnership between the FBI and the National White Collar Crime Center, said auction fraud has been identified as the primary source of disputes and web fraud.

Nearly a quarter of the auction fraud complaints were about non-deliverable merchandise and non-payments.

eBay, the largest online auction site, changed its privacy policy so that it could warn customers about users who have been suspended for fraud. It also shares information about alleged fraud with law enforcement agencies and this is believed to be the reason that online auctions have such a large percentage in the fraud figures.

The next biggest scam was the 'Nigerian letter' where victims are promised large sums of money fraud in return for their bank details. This fraud was responsible for more than 15 percent of complaints and cost the victims on average $5,575.

Other frauds included identity theft which cost the victims on average $3,000 a head and investment frauds which cost on average $1,000.