It has taken trolley rage out of the lives of millions, but today confidence in online shopping was knocked by new findings that problems are rife for customers buying groceries over the internet.

Faults were found in almost all the web-based services in the survey, including ordered items missing from deliveries and products arriving late.

The survey, by trade magazine the Grocer, found numerous problems when it attempted to buy the same 33 products from websites run by Sainsbury's, Tesco, Asda, Iceland, Waitrose - which operates outside London - and Ocado, a warehouse-based partnership with Waitrose that delivers within the capital.

It took 80 minutes to order the 33 items from Sainsbury's, and in spite of the company's promise to deliver them within 24 hours, they arrived three hours late and were two products short. Ordering from Iceland's website took 135 minutes, and the products took eight days to arrive, as Iceland said it could deliver only in a two-hour slot once a week.

The order from Asda, which took 130 minutes to place, was supposed to arrive within 48 hours but turned up 20 minutes late with 13 items listed on the receipt missing. Tesco's website was one of the better performers. It took 50 minutes to place the order, which arrived within the promised 24-hour period, but mistakes had been made with the size of products and two items were included which had not been ordered. Waitrose and Ocado were praised, with both orders arriving complete and on time.

A Tesco spokesman said: "We obviously try hard to get things right for customers and on the whole we do. However, Tesco.com is dealing with about 100,000 orders a week and thankfully mistakes are rare."

A spokesman for Asda said: "The overwhelming majority of our shoppers get a very good service but sometimes these things happen and we are investigating."