Several emails have been received by Fife residents, which appear to be authentic requests from auction sites such as eBay and also Internet banking sites urging users to update their credit card details.

But once the details are obtained, funds are swiftly removed from accounts.

Another con involves sending a “second chance offer” to an eBay bidder who was unsuccessful in buying an item. The bogus message claims the winning bidder failed to pay.

In some cases hundreds of pounds have been sent in good faith, only to fall into the hands of fraudsters.

A police spokesman said one Fife resident attempted to sell a musical instrument on a specialist web site.

The seller received an e-mail from an interested party and a price of £325 was agreed.

The buyer agreed to send a cheque in payment and the item was to be sent to an address in Nigeria.

A few days later a cheque arrived for £2500 with a request that the remaining funds be returned.

But when the cheque was presented to the bank the seller was told it was fraudulent and was one of a number of similar scams.

Inspector Alex Harkness of Fife Police encouraged the public to be vigilant.

He said, “This is a very worrying trend. The people who are committing these crimes are very professional.

“They create web sites with links that appear to be connected with the genuine sites. People are then conned into passing over credit card or bank details and money is then stolen from them.”

Mr Harkness added, “My advice would be never to send credit card details as a result of an e-mail request.

“No authentic company or bank will ever ask you to send personal details by this method but will ask you to log on to the secure section of their site using your recognised passwords etc.”