A new way of paying for internet shopping could pave the way for millions more people to buy their groceries online.

The 3V voucher, bought through Payzone terminals in much the same way as a mobile top-up, using a plastic swipe card, carries a randomly generated Visa card number that can be used to buy from any website that accepts Visa cards.

3V Transaction Services, the company behind the voucher, said a study of attitudes to online shopping found that one fifth of the population wanted to shop online but didn't because they didn't have a bank card, were worried about fraud or feared losing control of their spending.

The company claimed the 3V Voucher - available in amounts from £20 to £200, with a £3.50 charge - would offer an ideal solution for such consumers and could boost online sales for the likes of Tesco and Ocado.

In a trial carried out in Ireland, Tesco was one of the most popular online retailers visited by shoppers using the voucher.

Kieron Guilfoyle, chief executive of 3V Transaction Services, said: "The trial found that time-strapped young professionals who didn't normally shop online used the service - with Tesco in the top ten sites visited. We would expect a repeat of that in England, with potential for other food retailers to benefit."

The vouchers are secure and can't be copied because extra security details are delivered separately to the customer's e-mail or mobile phone when they buy them.