Britain's biggest supermarket group, Tesco, has reported a quadrupling of online sales for December.
It also says weekly turnover is now running significantly above £5m sterling.
John Browett, the head of Tesco's online trading arm, declined to give a total value for December sales but said turnover was four times higher than a year earlier and that Tesco.com was still expanding to meet demand.
Tesco dominates the UK's online grocery trade - it says it commands 80% to 90% of the market - and is due to issue a trading statement covering the Christmas period on January 16.
Mr Browett said that almost half of the growth in online sales was new business -- shoppers who would not have ordinarily bought their groceries at a Tesco supermarket.
More than 60,000 new customers registered with Tesco.com. Tesco said it was Britain's most prolific online retailer, delivering more than 30 million items in December - 10 times more than rival Amazon.co.uk.
Tesco Ireland started its online service in areas of counties Dublin, Kildare, Meath and Cork in October and a spokesperson said it is going well.
