The Central Bank has said it is concerned at the "unacceptable continuing delays" by Ulster Bank in fully resolving the failure of its payment system and the consequent impact on its customers.
A systems failure has impacted on more than 150,000 of the bank's customers here, with many not receiving payments and salaries into their accounts.
In a statement this evening, the Central Bank said it had been, and continued to be, in daily contact with Ulster Bank and its parent, RBS Group, since the issue first emerged on June 20th.
"The deputy governor met with Ulster Bank and RBS senior management earlier this week and spoke with the CEO of RBS earlier today to emphasise to him the importance of RBS addressing the continuing delays in resolving the technical issues which are impacting Ulster Bank customers," the statement said.
The bank was working with the UK Financial Services Authority and the Bank of England in "investigating the root cause of the issue at the group level and how this has impacted Ulster Bank’s payment systems".
Ulster Bank, meanwhile, said about 80 of its branches had extended their opening hours to 7pm for the remainder of this week to assist customers who could not get to their bank duirng working hours.
It has also extended the opening hours of its 60 Saturday opening branches from 10am to 3pm. On Sunday it will also open 22 branches from 10am to 1pm.
Some 38,000 customers visited the bank's branches yesterday and it handled 15,000 calls through its call centre, it said.
Customers may contact the bank over the weekend from 8am-10pm on 1800 205 100.