BAILED-OUT AIB has launched an investigation into why some of its customers were charged twice for the same transaction on two days this week.
It is understood that some of the bank's customers were victims of a bank error on March 25 and March 26.
In a statement the bank acknowledged that it was looking into the matter, but didn't know how widespread it was.
"AIB is aware of an issue and its incident team is currently investigating, with a view to reversing it as soon as possible.
"There will be full reimbursement to any customer impacted," the statement said.
Speaking on Morning Ireland, John O'Dwyer, AIB's head of technology, media and telecommunications banking, said the situation "is well in-hand".
He gave an assurance that no customer would left be out of pocket as a result of the issue.
It's the second time that AIB has been linked to double charging some customers in just over a year.
Last January, people who used a card for transactions ended up being charged twice when they used terminals supplied to retailers by a firm part-owned by AIB.
The blunder involved some 48,000 card users who made a combined total of 88,000 transactions, valued at €5m.
Anyone who had a refund processed on the same day ended up getting double the amount of money they were due. The problem with 15,000 point-of-sale terminals supplied by AIB card services led to the double-charging.
However, the bank promised that the thousands of shoppers who were double-charged would not end up having to pay bank charges or overdraft fees because of the blunder.
Earlier this year, customers of Bank of Ireland were mistakenly charged twice for transactions on their Visa debit cards.
The bank later confirmed that the issue arose due to the duplication of a file, rather than as a result of a technical glitch in the processing system.