The new feature launched by Barclays could help those dealing with gambling problems, for example, to cut off their spending in betting shops and on gambling websites.
People can also block their own spending in pubs and bars.
Barclays said it has developed the tool to turn off certain types of spending with vulnerable customers in mind.
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 feature is now available to all Barclays debit card customers, and will be rolled out to credit card holders in the near future.
Barclays said it will 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.
The bank’s work has used research from the Money and Mental Health Policy Institute set up by consumer champion Martin Lewis.
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.
These include people with mental health issues and addictions as well as those who rely on carers or a guardian to handle their finances.
Mr Lewis said he hopes other banks will follow suit.
He said: “Mental health and debt is a marriage made in hell. 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 - which blocks purchases made from these services, not the numbers themselves - as well as gambling websites and betting shops.
Catherine McGrath, managing director at Barclays, said: “We work with a range of advisers and partners, as well as consulting with our customers, to identify how our customers’ needs are changing and what works for them.
“This new control feature is the latest new service that we have introduced in the Barclays Mobile Banking app that aims to give all of our customers a better way to manage their money in a simple, secure and effective way.”
Chris Fitch, vulnerability lead at the MAT, said: “Technology that meets everyday banking needs, while recognising the challenges many of us face in our lives, is the way forward.
“Giving everyone more control is the key to achieving this - whether this is someone who wants to be less vulnerable to fraud, or a customer who is trying to take charge of their gambling.”
Marc Etches, chief executive of GambleAware, said: “GambleAware welcomes this initiative by Barclays, which we hope will encourage other banks to do the same.
“There are 430,000 problem gamblers in Britain and a further two million at risk, and initiatives like this can play an important role in helping to reduce gambling-related harms.”