Ulster Bank has apologised to customers after a technical problem left them unable to access accounts or withdraw money for the second time in nine months.
It came after a computer meltdown last June left millions of customers unable to withdraw cash for up to a week.
Customers began reporting problems with cash machines and cards being declined, as well as accessing their accounts online and via telephone, last night.
RBS, the owner of Ulster Bank, initially issued apologies about the inconvenience on Twitter at 11.30pm.
The problem was later resolved at around 1am.
A spokeswoman for RBS said: “We are disappointed that our customers have faced disruption to banking services for a period this evening, and apologise for that. All services are now running as normal again.”
She added that any customers having continued difficulties should contact customer services.
RBS was unable to give details about why the service was affected and whether it stopped payments and direct debits being paid.
Stephen Hester, the chief executive of RBS, was forced to apologise last June after millions of customers in Ireland and the UK were left unable to view an up-to-date balance following a software update.
It also affected payments such as direct debits for bills and some wages were not received.
PA