Ulster Bank says it is continuing to experience ''a major technical issue'' which is resulting in a one day delay in the processing of certain payments.
It has estimated the glitch has impacted over 100,000 people.
The bank has apologised for the delay and said it appreciates it is having a significant impact on many of its customers and customers of other banks.
''We are working to resolve the problem as a matter of urgency,'' the bank said in a statement.
''We are working hard to minimise the impact and will ensure that those who are affected do not suffer any financial loss'', it added.
It said that its customers can access their money as normal through the branch network. ATM and Anytime services are also fully operational, but are also reflecting the one day delay.
The technological problems also affected Ulster Bank's sister bank in the UK, NatWest, yesterday. The problem was rectified in the UK, but the root cause of the problem is still not resolved here.