The service, PayQwiq, enables shoppers to connect debit and credit cards to the app and purchase products on their mobile by scanning QR codes that display on-screen.
The app, which is available for iPhones or Android smartphones, is similar to Android Pay and Apple Pay.
A Tesco spokesperson said: “At Tesco, we are always looking to make the shopping experience simpler and easier for customers and that’s why we’ve developed PayQwiq.
“Feedback from customers who have used PayQwiq has been very positive, and we’re delighted to extend the availability of PayQwiq to Tesco customers in more locations.”
The PayQwiq app was only available in Edinburgh and London on an invite-only basis. However, it will now open up to shoppers across 600 stores in the two trial cities, as well as Plymouth and Northern Ireland.
In July, Tesco bakery chief Gordon Gafa will head a star line-up of speakers at this year’s British Society of Baking (BSB) conference in October.