Ulster Bank has apologised to customers in Northern Ireland following the latest problem which saw some customers being debited twice for a single transaction.

The bank, which suffered a significant IT problem in 2012, said it was working to correct the problem and restore funds to customers’ accounts by tonight. However, the bank has not yet given any indication how many accounts were compromised by the technical problem.

The number of cash-dispensing ATMs affected by the fault has not been confirmed.

A spokesman said: “We are aware of some issues with duplicated debits, we are working hard to fix this, sorry for any inconvenience.”

The bank stressed yesterday that customers would not be left “out of pocket”.

“We are aware of an issue regarding duplicate ATM transactions involving some Ulster Bank customers between 4.15pm on Easter Monday and 4.15pm on Tuesday afternoon.

“We are working to correct this for affected customers and restore money to accounts tonight.

"Customers will not be left out of pocket and can contact us if they require further assistance. We apologise for any inconvenience caused."

Massive systems failure

The bank had to apologise for problems last December when some services were interrupted.

This followed a massive systems failure in 2012 when large numbers of customers lost access to their accounts.

Some 100,000 customer were affected by the fault which resulted in 80 branches staying open late to deal with the backlog of transactions.

Ulster Bank said the original technical problem was caused by a software upgrade to the payment processing system which was corrupted.