Ulster Bank has apologised to its customers who experienced issues logging into their online and mobile banking accounts this morning.
A spokesperson for the bank said the issue has now been resolved and "no customer will be left out of pocket as a result of this".
It is the latest in a series of technical issues the bank has reported in recent years.
In the UK, Ulster Bank's parent, Royal Bank of Scotland, said it was working to fix issues with its Nat West online and mobile banking services.
RBS is the fourth financial services firm to suffer an outage in the UK this week, with Barclays, the Co-operativeBank and fintech company, Cashplus, all apologising to their customers for disruptions to their services.
