Customers living within a three-mile radius of Asda’s Halifax, Rotherham and Poole stores can order up to 70 items from Asda.com for express delivery within an hour.
They can also order a larger basket and select a slot within the next four hours, with no limit on the number of items able to be purchased.
The Leeds-based grocer said there is potential to quickly roll out the service to more stores if it proves popular with customers.
Each delivery will be charged at the flat rate of £8.50 and there is no minimum spend per basket.
Asda said it will become the first grocer to offer its full online product range.
Rivals, including Bradford-based Morrisons, Tesco and Sainsbury’s, already offer one-hour – or faster – delivery services through Deliveroo, Uber Eats, Amazon and other providers – although none offer a full range of products.
Asda is also extending its partnership with Uber Eats from 200 to more than 300 stores, with 500 products including fruit, vegetables, beer, wine and spirits and meals for rapid delivery.
Simon Gregg, Asda’s vice president of online grocery, said: “After successfully trialling an Express Delivery service, we know this is something that our customers want as part of our online grocery proposition and we are delighted to be able to offer this service to even more customers.
“The launch of our new Express Delivery service and extension of our existing partnership with Uber Eats to 300 stores means that customers can get their order delivered to the doorstep at market-leading pace.”
Morrisons offers same-day rapid deliveries as part of its tie-up with Amazon, which also offers its own Amazon Fresh products.