Ulster Bank is seeking around 50 voluntary redundancies from staff across its branch network in Northern Ireland.
The lender said the move has been taken as part of “ongoing efforts to build a strong and sustainable bank”.
No branches in the Republic of Ireland will be impacted by any changes.
In addition, from 7 May Ulster Bank will cease to open on Saturdays at 11 of its branches: Armagh, Ballymena, Bangor, Coleraine, Downpatrick, Dungannon, Enniskillen, Magherafelt, Newtownards, Omagh and Portadown.
Following the announcement, IBOA - The Finance Union said it was “extremely concerned about the impact on customers as well as the increased workload for remaining staff”.
It added that “the latest development will only exacerbate existing difficulties and undermine Ulster Bank’s ambition of being ‘number one for customer service, trust and advocacy’.