KBC Bank Ireland is to close four of its 16 branches or "hubs".
The outlets impacted are Dundrum in Dublin, Greystones in Co Wicklow, Naas in Co Kildare and Kilkenny.
The company wouldn't say how many jobs will be lost by the move.
But it is understood there will be some redeployments and new roles created elsewhere and that the final number of redundancies is expected to be less than 20.
The move follows a review by KBC of its hub network.
"As we are a 'digital first’ retail banking and insurance model, we continuously review our services to meet the changing needs of our customers," said Darragh Lennon Director of Distribution at KBC.
"We have seen a notable change in our customers’ banking behaviour with a clear acceleration towards digital banking, which has necessitated changes to our hub network."
"We understand that customers still want to access services through our hubs, and they continue to be an important part of our business model."
In the future the bank said customers who had previously used the Dundrum, Greystones and Naas hubs would instead be served by the Stillorgan and Maynooth branches.
Its hub on Swords Main Street will move to the nearby Pavilions Shopping Centre.
"The Stillorgan and Swords hubs will extend their opening hours to seven days a week," it added.