Mobile banking users can now block certain types of spending in a move which could help people gain control of their finances.
The feature, launched by Barclays, was developed with vulnerable customers in mind, such as those struggling with addictions.
For example, those dealing with gambling problems could cut off their spending in betting shops and on gambling websites.
Customers can also block their own spending in pubs and bars.
A button within the Barclays mobile banking app enables customers to choose which types of retailers they are able to spend with.
Attempted payments that fall within the "turned off" category will be automatically declined.
The new tool is now available to all Barclays debit card customers and will be rolled out to credit card holders in the near future.
The bank said it would help all its customers take greater control over where their money can be spent, as well as making them less vulnerable to fraud and scams.
Barclays' work has used research from the Money and Mental Health Policy Institute set up by consumer champion Martin Lewis.
More from Barclays
It also worked with the Money Advice Trust (MAT) to identify types of customer who would particularly benefit from being able to decide how and where their money is spent.
"Mental health and debt is a marriage made in hell," Mr Lewis said.
"Many with mental health issues struggle to control their spending – whether through gambling, shopping or premium phone lines – and I commonly hear from people with thousands of pounds of debt as a result.
"This is one reason why I set up the Money and Mental Health Policy Institute charity – and its detailed research shows the power of giving people more options for control tools that can add friction to this type of spending."
Barclays has five retailer groups where customers can control their spending: groceries and supermarkets, restaurants, takeaways, pubs and bars, petrol and diesel, premium rate websites and phone lines, as well as gambling websites and betting shops.
Catherine McGrath, managing director at Barclays, said the new feature "aims to give all of our customers a better way to manage their money in a simple, secure and effective way."
Culture Secretary Jeremy Wright said the move could "help people protect themselves from the risk of gambling-related harm."
More from Barclays
He added: "This is an area where both industry and government have important roles to play.
"I urge others in the banking sector to follow suit."