Scores of Halifax and Lloyds TSB customers have their cards rejected and been left unable to use some ATMs across the country.
Some customers reported having to leave their shopping behind while others said they have been left unable to access their bank accounts, just before the weekend starts.
Customers have been venting their frustration at the hitches at Lloyds and Halifax, which are part of the same banking group.
A Halifax spokeswoman said the hitches were the result of a “systems failure”, which has affected the group’s telephone systems as well as ATMs and online services.
She said: “The systems are now up and running and we are working through the backlog. The entire backlog will be processed today.”
Shopper Marc Dewhurst said he was visiting the Meadowhall centre in Sheffield when he tried to pay using his Halifax card but it was declined, despite him having the cash in his account.
He said: “Luckily I had just taken £50 out of a cash machine 15 minutes earlier.
“I went round to the Halifax and saw people shouting at the staff.”
Twitter users also took to the website to express their panic at their cards not working.
One customer wrote: “Just had a major panic, couldn’t access my bank account at the atm, apparently its #halifax problem not mine.”
In June, Stephen Hester, chief executive of RBS, apologised after a computer glitch at high street bank NatWest left hundreds of thousands of customers unable to complete transactions is fixed.