They can log in at www.ocado.com/lite using a browser-enabled mobile phone, PDA or other handheld device to do a full shop, amend delivery slots or add products via the search function or their favourites list.
Ocado said that, while it was not meant to be as 'feature rich' as the full website, the only major function not available on the site was registration of new customers.
A spokeswoman for the online grocer said: "We are constantly innovating to make our service more appealing and had requests to develop a service customers can use on PDAs. We built this to meet that demand."
She said several thousand customers were now using the service on the go and when not near a PC, boasting: "It is the best PDA-based website in the UK."