ULSTER Bank has apologised to customers after yet another glitch caused widespread difficulties for accessing cash at ATMs.
The financial institution said that services are back to normal this morning after another major technical glitch.
IT systems including online and telephone banking, cash withdrawals and payments were affected last night.
The issue is the second embarrassing problem for the banking group, which includes RBS, NatWest and Ulster Bank, in the space of just nine months.
Last year consumers were left in the lurch for several weeks after computer faults caused disruption at Ulster Bank. Tens of thousands of customers were unable to access their accounts – in some cases for more than a month.
RBS, NatWest and Ulster Bank had to extend opening hours at their branches to assist customers who had been unable to pay bills, move money or whose salaries had not been paid.
That problem was reported to be caused by an update to the software used for processing payments.
And last week the bank demanded around €30,000 each from 1,300 mortgage customers that they undercharged.
Last night's problem affected customers withdrawing cash at ATMs and cards being declined.
"We are aware of the problems our customers are having and apologies, we will provide more information as soon as we have it," the group said.
The CEO of the Consumer Association Dermott Jewell said that it raises serious concerns for account holders.
He said that it is important that the group implements a system that is "robust".
"It raises very serious concerns about the independence and the quality of the service behind the bank," Mr Jewell said.
"The vagueness that this was just a technical problem is unsatisfactory. It affected quite a significant amount of people.
"We must remember that consumers are paying for this service and it is just not up to scratch.
"RBS Banking Group and NatWest were able to resolve their system problems quicker."
Mr Jewell said that Irish consumers have the right to know what exactly happened.
"The idea that it is an internal technical glitch is not satisfactory. If this is a system under attack, then we need to know about this.
"The risk still seems to be there."
Mr Jewell said that they hope that the Central Bank can take some action here to liaise with Ulster Bank and the UK authorities to try to understand what happened in that system.
"All eyes turn to Ulster Bank in relation to confidence to the future," he added.
"This has not been good for customers and it has certainly been bad for Ulster Bank."