Some Ulster Bank customers may not see a normal service until mid-July, the bank said today as it works to tackle its IT meltdown.
Ulster Bank customers have had problems with their account balances updating since the hitches began on June 19, which also caused chaos for people who bank with NatWest and Royal Bank of Scotland (RBS), which are part of the same banking group.
RBS Group has had greater difficulty restoring the problems for Ulster Bank customers than the other two banks, but it said that the speed with which it has been able to bring accounts up-to-date has increased significantly in recent days.
It said in a statement today: "We now expect that next week (commencing July 9) will be the final week of any significant delays for Ulster Bank customers.
"We expect gradual, but significant and noticeable improvements throughout the remainder of this week and next.
"It is our expectation that by the week of the 16 July the vast majority of customers will return to a normal service, barring any residual reconciliation required."
Due to the way the technology was set up when the three banks were integrated, Ulster Bank payments happen to follow in sequence after those of NatWest and RBS, which "in no way" reflects any priority given to customers, RBS Group has said.
The group said yesterday that "a small number" of customers with personal loans had been charged twice.
It has promised that no one will be left permanently out of pocket as a result of the problems, which caused people's wages not to show up in their accounts and disrupted house sales and holidays.
Ulster Bank chief executive Jim Brown said: "We know customers are frustrated and they are right to be. Our efforts to fix this are paying off and over the last few days we have been able to gain a much clearer picture about when we expect all systems to be largely back to normal.
"We expect gradual and significant improvements for our customers and each day we will see more transactions processing, fewer problems with our systems, and less inconvenience for our customers.
"I would also like to say that throughout this incident a number of other banks have worked with us to process vital payments and I'd like to thank them for their support.
"We apologise again to our customers and all those people who have been affected by this problem. We appreciate the patience that has been displayed and we will keep everyone informed as we make progress."
Ulster Bank said a number of its core banking systems have continued to operate as normal throughout the problems.
RBS Group chief executive Stephen Hester said last week that he will forgo his bonus this year because of the chaos and has promised a "full and detailed investigation".