The Financial Services Union, which represents bank workers, has said its members are at breaking point dealing with the increased workload caused by the exits of Ulster Bank and KBC.
The union has commissioned a survey of its members, which shows that 88% of respondents feel stressed at work either on a regular or very regular basis.
The study found that 73% feel their workload has increased due to the exits of Ulster Bank and KBC.
Speaking before the Oireachtas Committee on Finance, Public Expenditure and Reform today, FSU General Secretary John O'Connell suggested the Central Bank should instruct Ulster Bank and KBC to extend their timelines for withdrawal until the end of 2023.
He also urged the banks to employ additional resources and staff to support customers changing accounts.
"It was clear from the outset that a change this seismic would require the setting of realistic timelines for completion, extra resources, and staff to cope with the additional workload and the collaboration of all relevant stakeholders to ensure that there is a transparent and coordinated approach to this major change project," he said.
"It is regrettable that the banks did not adopt this approach from the start," he added.
The union also repeated its calls for the Central Bank to convene a taskforce to coordinate an agreed implementation plan containing a range of measures to ease pressure on staff over the coming months.
Mr O'Connell also claimed that Ulster Bank were aware when announcing a six-month deadline for customers to close their accounts and move them elsewhere as required, that the system was not ready to cope with the resulting workload.
"We have growing concerns for the health and safety of staff, faced every day now with customers frustrated because they cannot open accounts on demand and dealing on the phone with customers still experiencing long waits and equally frustrated," he said.
He also said that the main retail banks have reduced their workforces over the last 12-18 months and it was impossible due to a lack of data to tell how many additional staff are needed.
"They have reduced customer services through branch closures, the removal of ATMS from local communities and reduced opening hours in their call centres," he said.
"This was all done with the knowledge that two main banks would be exiting the sector."
Sinn Féin Finance Spokesman, Pearse Doherty, questioned why the banks were still letting staff go through redundancy at the same time as they were bringing in new contract staff to assist with the influx of new switching customers.
He also claimed the Central Bank should not be letting the banks issue letters to customers instructing them to start closing their accounts, until the sector is ready.
Asked by Social Party and Solidarity TD, Mick Barry, whether the Central Bank should put a moratorium on further redundancies at the banks until the issues are resolved, Mr O'Connell said it would be helpful in order to keep skills in the sector and stabilise the situation.
He also suggested that the regulator should set standards for customer service.
Mr O’Connell said KBC’s plans envisage all accounts being closed by August next year and Ulster Bank’s timeline would see that happen by March.
Mr O’Connell said if that was not a "recipe for chaos" he did not know what was.
Labour Finance Spokesman, Ged Nash, said it was absolutely clear that the FSU had "called it right" in expressing concerns about the timelines and preparations for the departures of the two banks.
He agreed this was why a taskforce is required to oversee the exits.
Mr O’Connell also claimed that the change process is now being used as "Trojan Horse" to force people to use digital rather than branch services, when in many cases they don’t want to.
Additional reporting Brian O'Donovan