Online fraud, caused by phishing e-mails, password-stealing, Trojans and other scams, has risen significantly over the past 12 months, the banking industry reported last week.
Banks lost £14.5m in the six months to June 2005 because of online banking fraud, up from £4m in the same period last year, the Association of Payment Clearing Services said.
The introduction of Chip and Pin technology, which is making traditional credit card fraud more difficult, is encouraging criminals to turn to the internet, Apacs said.
Although online losses are small compared to the £218.4m credit card fraud reported by banks in the six months to June 2005, banks are concerned that online scams could damage their reputation.
Trials are underway of two-factor authentication technology, at Lloyds TSB, HSBC and Barclaycard.