Up to 125,000 Tesco Bank customers will see their minimum credit card repayments rise by around £20 a month from March.
The move comes as part of the lender's bid to combat persistent debt, and further support will be available for those struggling to make repayments.
Here, Which? explains how the new rules will work and the steps you can take to pay off your credit card debts more quickly.
Tesco cardholders currently have their minimum payments calculated based on three clauses, but Tesco will soon introduce a fourth clause.
This means a customer's minimum payment will be the greatest of the following four values:
The change will only affect customers who took out credit cards with Tesco between November 2017 and May 2020.
Cardholders who've signed up since May 2020 are already subject to the above rules.
Customers with 'Foundation' credit cards and those still on their introductory periods will also be unaffected.
Tesco says it is making the change to help customers avoid falling into persistent debt.
It has sent out letters to all customers who will be affected by the changes and has urged cardholders to get in touch with any concerns.
A spokesperson said: 'From March, a small proportion of our credit card customers will see a change in the way their minimum payments are calculated.
'The decision was taken to help customers pay down their credit card debts more quickly, resulting in them having lower interest charges and reducing the risk of them entering persistent debt.'
If you wish to close your Tesco credit card before the changes come into force, you should do so by 25 February.
Tesco says customers who may have difficulty affording the new minimum payment have been identified and will be excluded from the change.
Any other cardholders who have concerns about making their minimum payments should get in touch with the lender before the change comes into force.
The rules introduced by Tesco and Barclaycard come off the back of the Financial Conduct Authority's (FCA) guidance on persistent debt.
In 2018, the FCA introduced regulations meaning credit card providers had to offer more support to customers in long-term debt.
The regulator defines long-term debt as when a customer has paid more in interest, fees and charges than they have towards their actual debt in an 18-month period.
If a credit card customer is struggling with their payments after 36 months, the provider must work with them to help repay their outstanding balance within a reasonable period.
If you're able to make your monthly repayments but want to spend less on interest payments, you could consider transferring your balance to another provider.
Some banks offer . These allow you to pay no interest on your balance for a specific amount of time (e.g. 12 or 18 months). You will usually need to pay a fee to transfer the debt, so you'll need to factor this in.
If you want to pay off long-standing credit card debt, the key is to pay more than the minimum payment each month if you're able to.
Minimum repayments are usually swallowed up by interest and any fees, with only a small amount going towards the actual balance.
And as your balance decreases, so too will your minimum payment, meaning it will then take you even longer to clear the debt.
With this in mind, it's best to take matters into your own hands.
If you're worried about paying your credit card, your provider may be able to offer you tailored support.