Danish owned National Irish Bank is closing 20 branches in November and will look for 100 voluntary redundancies as it changes the structure of its Irish retail business.
The bank said that the traditional branch model is no longer the cornerstone of personal banking.
It said the closures will go some way to its coping with the changed banking environment in Ireland, and shifts in customer behaviour.
It said it will also create an "efficient business model" to support the bank's future strategy.
Last month Danske had its credit rating downgraded by Standard and Poor's because of the continuing problems at National Irish Bank.
NIB said it plans to deal with its customers over the phone through a new Personal Banking Centre.
Danske Bank has taken more control of its Irish operation as part of a wider restructuring of its overseas operations.
Last month it announced the setting up of a wind-down unit for €4.7 billion of commercial and investment property loans.That is 56% of NIB's book.
The bank expects further impairments of €670m to €940m on its Irish loans until the end of 2014, and for bad debts to return to normal in 2015.