Ulster Bank customers are experiencing more technical problems this morning.
The bank confirmed that it is aware that some people are having trouble with their accounts this morning - and said it is working to fix the problem.
It also said that no one will be left out of pocket as a result.
The incident is the latest in a series of technical problems for Ulster Bank. Earlier this month, thousands of customers were left unable to use their credit or debit cards because of a glitch.
It is just over a year since customers were locked out of their online accounts for a month because of a series of technical issues.
On its Twitter helpdesk service the bank apologised to customers and said they were working to have the issues fixed as soon as possible.
@morningireland We are aware of the issue now and our team is looking into this as a priority. Hopefully its fixed very soon ! IK
— Ulster Bank Help (@UlsterBank_Help) December 12, 2013
Customer service agents and the bank’s helpdesk were hit with a barrage of complaints for the second time in a week after another embarrassing technical failure.
“We are currently missing a batch of credits however we are investigating this as urgent,” advisers told customers online.
There was no immediate comment from the bank in the Republic or the North.
Many customers claimed they were unable to access current transactions, wages being paid into accounts and other payments.
Ulster Bank’s parent company Royal Bank of Scotland suffered a major IT fault last week that left customers unable to use debit or credit cards for a three-hour spell on what was expected to be the busiest online shopping day before Christmas.
An estimated 750,000 RBS, NatWest and Ulster Bank customers were affected.
Days later, its websites fell victim to a cyber attack which also affected some customers.
RBS, 80% owned by the UK government, has been beset by system failures, including a major meltdown last summer, and RBS chief Ross McEwan admitted it had not invested properly for decades.
Ulster Bank revealed that some of its customers with euro accounts were affected in the latest issue.
It is understood the problem centres on payments coming into accounts held in the Republic and payments being made in euros.
“Some inward credit transfer files were delayed through our payment system overnight and we are working to resolve this issue for customers as soon as possible,” the bank said in a brief statement.
It is not known how many customers or payments have been affected by the glitch.