The advice follows the recent spate of a 'phishing' scams to hit banks including Bank of America, Citibank, Hansabanka, National Australia Bank, Barclays Bank and LloydsTSB.

Apacs says the guidelines were issued following a two-tiered e-mail scam that has emerged over the past two months. The first part of the scam involves e-mails being sent to consumers claiming to be from banks, asking them to 're-register' or 'reactivate' their accounts at a replica bank Web site.

NHTCU says typically the fraudsters behind these fake sites are located outside of the country and need a UK intermediary to transfer money directly out of their victims' online accounts.

In order to achieve this, the fraudsters send spam e-mails to people offering them the chance to make some easy money by acting as a UK agent to a business overseas. Customers receive funds into their online accounts and send them on to fake businesses, minus a transaction fee which the customer keeps. Once the transactions are completed, the whole of the inital deposit is cancelled, leaving the account holders out of pocket.

Last month, online banking customers in Australia and New Zealand were targeted by a similar scam that was being run out of Denmark.

Detective Chief Superintendent Len Hynds at the NHTCU, says: "The message is - don't allow yourself to be duped. Remember, if an unsolicited money-making offer looks too good to be true, then it probably is."

David Lennox, director, fraud and physical security, BBA, says while these types of fraud have always been with us, the Internet is now being used as the preferred medium for attempting to carry them out.

The guidelines issued by NHTCU, Apacs and BBA urge online customers to always access Web banking sites by typing the URL into the browser. Customers are also advised to check statements regularly and to be especially wary of unsolicited e-mails offering easy ways to make money.