This lack of security increases the chances of users being targeted by fraudsters.

One method used, known as "phishing", starts with a spoof e-mail directing users to a fake website for their bank and tries to trick customers into giving away their log-in details.

Most of the 585 online customers surveyed on behalf of the Association for Payment Clearing Services said they would ignore such e-mails. But 4% admitted they would automatically respond to a message supposedly from their bank.

Another problem area uncovered by the research was users' attitudes to passwords for online accounts.

Just over a third said they recorded their password somewhere despite advice to commit it to memory.

A further 18% had told someone else their password, 60% had never changed their password, and 28% used the same password for other internet services.

The results coincide with the launch of a new website designed to help online banking customers avoid becoming victims.

It explains various threats users should be aware of, how to report problems and provides updates on the latest dangers.

APACS corporate communications director Sandra Quinn, said:

"With 14million people banking online in the UK, the 4% who say they would respond to a scam e-mail allegedly from their bank is still too high and they could unwittingly be giving fraudsters access to accounts.

"The new website sets out the simple steps you need to take and will hopefully encourage anyone who hasn't thought about protecting themselves to start doing so now."

Detective Chief Superintendent Mick Deats, head of the National Hi-Tech Crime Unit, said:

"We are pleased to lend our support to this new website which is part of the banking industry's efforts to make customers aware of what they need to do to stay safe online.

"Meanwhile, we will continue to work behind the scenes to bring the gangs perpetrating these crimes to justice."