All ATMs at Bank of Ireland branches around the country are out of service.
A spokesperson said it is a network issue and technicians are working to fix the problem.
"BOI is aware that some channels are currently out of service," the bank posted on social media.
"We’re working to rectify this ASAP and will provide further updates as soon as we can.
"Credit cards are working as normal and point-of-sale transactions are an option too.
"Apologies for the inconvenience caused."
The Bank of Ireland app is also affected.
All credit card and point of sale machines are operating as normal, while cheques and cash can be lodged at branches that have a cashier.
