Ocado is shaking up online grocery retailing as it launches price cuts on almost 4,000 Waitrose own-label food and drinks products.

The home-delivery retailer launched an internet-only-prices guarantee on Monday on a wide range of Waitrose products including fresh produce, as well as grocery, meat, fish and household lines. The new deal means that those lines are now cheaper to buy at home via the Ocado website than in Waitrose stores.

Ocado said its aim is to keep giving cost-conscious shoppers, including newly converted customers poached from Tesco and Sainsbury’s, greater choice, while introducing the quality Waitrose name to new customers and offering better value.

Jason Gissing, co-founder of Ocado, said: “This is a seminal moment in online grocery retailing. People are used to paying less for books, CDs and holidays online, now they can pay less for their supermarket shopping too. Online grocery shopping is rapidly becoming mainstream in a way that online consumer electronics and travel did a few years ago - I think Ocado and Waitrose are making the next big retail move; this is a seismic change for the industry and a big draw for Tesco and Sainsbury’s customers who are already finding us a source for great value and quality.”

The move is likely to put pressure on Tesco and Sainsbury’s to offer free deliveries to all their customers. Both chains already offer free delivery sporadically often as a special offer, or depending on spend and time and day of delivery.

Gissing said: “Waitrose’s managing director Mark Price is right to say we’re facing a challenging economic environment, and we share his goal to make Waitrose goods even more accessible. We’re delighted to be able to make these price cuts for customers; it’s never been a better time to enjoy, and save money on delicious Waitrose groceries.”