Supermarket shoppers will need to supply their mobiles to use the Asda loyalty scheme after it tightened its security.
The "Rewards" app now require customers to input the additional information, as first reported by MoneySavingExpert.
It comes after some loyalty scheme users claimed cash saved in the app had disappeared and even been spent far away from their homes in stores.
Others were unable to access their accounts or use log in details. Dozens of Asda Rewards customers say they had problems.
Asda denied their had been "a widespread security issue" with its app and pointed to weak online personal security as the reason.
But users of its loyalty scheme users will now need to input a mobile phone number into the app before being given receive a one-off one-time passcode.
This will be sent via text to input into the app before you can continue to use it.
You will only be asked to do this once, and the mobile device you complete the process on will become your trusted device.
Customers should only be asked to do this again if they change their password, or if they want to log into the app on a different device.
If not already a customer an app must be first download from the Apple App Store and Google Play Store.
They can then register for rewards or sign in with your existing account they have alreadyshopped online with Asda.
The Mirror reported in August last year how Asda launched its first-ever loyalty scheme nationwide following a successful trial.
As the price of food and essentials skyrocket, the retail giant is introducing Asda Rewards across the country.
Shoppers can earn vouchers to save money on future grocery bills at Asda by using the app.
The scheme was first trialled in its 16 stores across West Yorkshire and the West Midlands last year - but it will now be implemented nationwide in 633 stores across the UK.
To get started, you'll first need to download the Asda Rewards app and create an account.
Each time you shop online or instore, you will be credited with Asda Pounds by scanning the barcode or logging into your account at checkout.
The Asda Pounds will accumulate into a Cashpot where the balance can be converted into vouchers to spend with the supermarket.
You can add to the Cashpot through missions and Star Products.
Different missions are added to the app regularly - they range from buying a certain number of products from a particular department, to spending a minimum amount over multiple visits.
