From this week, shoppers in four parts of the country - south Wales, the south coast, the M4 corridor and Scotland - will be able to order their groceries from a new version of Asda.com, which has been redesigned to make it easier to navigate.
The new site was trialled at the beginning of the year in Grimsby, Doncaster and Rotherham before being expanded to cover the whole of Yorkshire and Lancashire.
By the end of June, the 55% of the country still using the old website would be switched over, an Asda spokesman said. By the end of 2009 the retailer would offer "not far off 100%" coverage and would cover as much of the UK as any other retailer, he added.
Asda currently offers 95% of UK households home grocery delivery, compared with Tesco's 98%.