A technology glitch at Ulster Bank has been resolved and customers affected will be reimbursed overnight.

The computer problem saw some of the bank's customers in Northern Ireland charged twice for withdrawals from ATMs between 4.15pm on Monday and 4.15pm on Tuesday this week.

It is unknown how many customers were affected.

In a statement, Ulster Bank said it was aware of the issue and apologised to customers.

"Customers will not be left out of pocket as a result and can contact us if they require further assistance," it said.