NATIONAL Irish Bank customers will no longer have access to branches from today when the Danish-owned operation shuts its retail outlets.
All 27 branches will shut, with the loss of 100 jobs.
Customers will now have to use An Post offices, telephone banking, go online to do their banking or drop into one of the new advisory centres.
Banking union IBOA said the closures were a black day in the history of National Irish Bank.
The bank has denied that the closures are part of a plan to close down its operations in Ireland – but it is changing its name to Danske Bank.
A bank spokesman said customers would be able to contact its personal banking advisers by phone between 8am and 8pm each weekday.
From Monday, new Danske Bank centres will be open in Waterford, Athlone, Cork, Limerick, Letterkenny, and across Dublin at the IFSC, Tallaght, Swords and Stillorgan.
The bank's head of business development, Jesper Nielsen, argued that people were more eager to do their banking by telephone and the internet, and less inclined to go into branches.
Last month, AIB closed 44 branches out of a total of 67 marked for closure this year.
Bank of Ireland closed a landmark branch in Limerick city, and it is also slashing services at 40 branches, instead of closing them. It will not accept cash in branches on certain days.
Permanent TSB is to close up to 19 branches out of a total of 92.
Ulster Bank is expected to close up to 40 of its branches next year. It has 146 outlets but the crash of its payments systems during the summer delayed branch-pruning plans.
EBS, which is now part of AIB, is expected to close a number of branches.