Ulster Bank's Chief Executive has said it will be several weeks before all issues with customers’ accounts will be fully resolved.
In an interview with RTÉ News, Jim Brown also said Ulster Bank expects to pay out "tens of millions of euro" in compensation.
Mr Brown said that while its systems are now running normally, there are problems with some unprocessed and duplicated transactions.
He said it would take some weeks to reconcile accounts fully and he could not put a finer timeframe on this.
Mr Brown also said the bank is finalising details of a compensation scheme that will be paid on top of automatic refunds of incorrectly-applied interest and fees.
Compensation will be paid for inconvenience and stress caused and the bank is working on the finer points of this with the Central Bank.
Mr Brown said that so far, no customers had left the bank and balances have remained flat.
He also confirmed that Ulster Bank is looking at moving its regulation to the Britain.
Asked about whether anyone would lose their job, Mr Brown said they would examine this when an independent report is finalised. This report will be published.
IT problems have affected hundreds of thousands of its customers for almost a month.
A technical problem during a software upgrade at its parent company RBS disrupted electronic transactions and created a massive backlog processing payments.
At least a third of Ulster Bank's 1.8m customers across the island of Ireland are thought to have been affected by the computer breakdown.
