Bank of Ireland has said systems that were down for much of the day are coming back online this evening.
ATMs are operational again and Banking 365 website and app services are being restored.
Some branches will stay open until 8pm to accommodate customers.
The bank has apologised for the inconvenience caused.
The cause of the problems is still being investigated.
Earlier the bank had said payments were being processed and debit and credit card point of sale transactions were still going through.
A spokesman said the issue was unrelated to problems the bank experienced yesterday with its payment systems.
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BOI is aware that some channels are currently out of service. 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.— Bank of Ireland (@talktoBOI) November 28, 2019
The spokesperson also said that people could withdraw money at the counter in Bank of Ireland branches.
The Central Bank said it was monitoring the situation and was in contact with Bank of Ireland in relation to the issue.
"Customers have a legitimate expectation of high quality, uninterrupted services, whether provided through traditional or online channels," it said in a statement.
"The Central Bank expects all firms to have adequate systems and controls in place and where issues that impact customers arise they should be addressed and rectified urgently, particularly as customers are increasingly using and becoming dependent on online and mobile banking services.
"In this regard, the Central Bank expects firms to communicate clearly and promptly with affected customers when a technical incident occurs, including details of the impacted service, details of alternative access to services and an undertaking that identifiable loss will be remediated.
"Our expectations have been communicated to banks."