Tesco has called on the UK advertising watchdog to intervene over Ocado's marketing campaign that claims the online grocery retailer is matching the prices of the UK's largest supermarkets.

In February, Ocado launched its "price-match" campaign, claiming to offer 3,500 branded goods at or below the prices of the mainstream supermarkets. The campaign carried the strapline: "Waitrose products at Tesco prices".

Tesco has argued that Ocado is regularly more expensive on at least 500 items.

"Ocado are not matching Tesco prices on hundreds of products despite their very clear and public promise to do so," a spokesperson for the UK's largest retailer told just-food. "We believe it is wrong for them to break this promise week after week and to mislead their own customers. This is why we have reported their poor behaviour to the advertising watchdog."

Ocado marketing and finance director Jason Gissing responded by suggesting the group checked its prices against Tesco's every week.

"We are not surprised that Tesco has decided to act with its customary aggression, but we are disappointed [that] it doesn't have more important issues to focus on. It has clearly realised that its initial response of price-cutting goods [that] we both sell has not worked," he said.