A glitch with Bank of Ireland’s online app reportedly allowed customers with no money to transfer funds and withdraw it from an ATM.
The technical blunder meant people were able to put money into a Revolut digital account and then withdraw it from a cash point.
Some claimed that they were able to access as much as €1,000 (£859), but the bank insisted the daily withdrawal limit is €500 (£429), according to Independent.ie.
Various videos circulating on social media showed long queues at ATMs in various cities, as well as some police guarding pay points.
The bank confirmed it was working on a technical issue that was impacting multiple services, including the mobile app and online banking portal, 365Online, on Tuesday.
It warned customers that any money transferred or withdrawn over normal limits “will be debited from their account”.
“We are conscious customers may not be able to check balances, but should not withdraw/transfer if they are likely to become overdrawn,” it said in a statement posted on X (formerly Twitter).
The issue comes after another IT outage at the bank in June, according to Independent.ie.
This did not result in people getting access to funds they did not have in their accounts.