More fears were raised this week over the safety of shopping on the Web after security breaches forced two high street retailers to shut down their Internet sites.
The latest blow to the image of e-tailing comes hard on the heels of similar problems at Barclays Bank and PowerGen sites.
Woolworths was forced to close down its Web site after receiving calls from customers who found they were able to read other customers' credit card details.
A Woolworths' spokesman said, "We acted immediately we were alerted and there were no illegitimate transactions. The retailer is working with its suppliers to identify the cause of the problem."
In a separate incident, Safeway closed down its Web site after several thousand customers were sent a spoof e-mail claiming that the supermarket had increased its prices by 25%.
"We're taking the incident seriously. The IT department is looking into all the possibilities," the company said.
There is no suggestion that either retailer was at fault.
Recent security problems have highlighted fears that companies are not testing security systems properly in the rush to get online.
John Higgins, director of the Computer Services and Software Association, said that online failures "in part arise from the pressure to cut corners with testing in the rush to get e-functions added to a company's business".