Company chief executive Jim Brown said despite the damage the ongoing scandal had caused, he did not accept those affected were set to transfer to rival banks.
It came as the Central Bank said it was concerned “by the unacceptable continuing delays by Ulster Bank in fully resolving the failure of its payment system and the consequent impact on its customers”.
Mr Brown said nobody affected would be left out of pocket and charges directly related to what happened would be waived — but he dismissed talk that customers would be given additional “sweeteners” to stay.
Labour senator and barrister Lorraine Higgins had called for charges to be waived for a number of months following resolution of the crisis as an apology to loyal customers.
However, Mr Brown told the Irish Examiner his firm was confident customers would stay with the crisis-hit institution.
“I really do apologise for the inconvenience caused to customers as a result of this issue,” said Mr Brown.
“Right now, our real focus is on customers and meeting their out-of-pocket expenses. We have received incredible support from customers and I do thank them for their support.
“We haven’t seen any evidence of that [switching to rival banks].”
Mr Brown said the bank’s review of what happened will focus on whether contingency plans were adequate.
He declined to comment on reports in the Financial Times that the wider Royal Bank of Scotland Group, of which Ulster Bank is a part, is considering suing a US software firm connected to the crisis.
Mr Brown said he expected the issue to be fully resolved for almost all customers by “early next week”.
This means people expecting monthly child welfare payments on Tuesday are likely to receive them.
Last night an Ulster Bank spokeswoman said: “To assist our customers who cannot get to a branch during working hours, approximately 80 of our branches have extended opening hours for the remainder of the week until 7pm. We are also extending the opening hours of our 60 Saturday opening branches from 10am to 3pm. On Sunday we will also open 22 of our branches from 10am to 1.00pm.”
* www.ulsterbank.ie or the helpline 1800 205100