Ulster Bank is to close ten of its non-cash advice centres temporarily from Friday.
It is also to temporarily cease Saturday opening in all of its branches and its Mobile Bank on Wheels service.
The move is being taken in response to the challenges being posed by the Covid-19 pandemic and is a result of much reduced footfall in branches.
"Numbers of customers visiting branches has fallen in response to social distancing and instructions from our health authorities to stay at home, but we recognise the criticality of the branch for certain customers," said Ulster Bank Managing Director of Personal Banking, Ciarán Coyle.
"Our ATM network will also continue to support customers who need access to cash."
The bank also warned that ad-hoc or temporary changes to branch opening hours should be expected in the coming weeks due to the day-to-day availability of staff and the need to ensure all staff receive breaks.
It is therefore urging customers to check whether a branch is open before setting off to visit it.
Priority access will also be given at branches to elderly and vulnerable customer and carers until 11am every day, it said.
The bank said the changes would support customers and protect customers and colleagues.
Two new dedicated phone lines, one for elderly and vulnerable customers and their carers, and a second for healthcare and emergency workers have also been set up.
The bank has also introduced a new online form for customers who are seeking a mortgage payment break to help speed up the process.
Ulster Bank says customers should only come to branches if they can't carry out activity online or on their app.
"We know that there are some delays on some of our telephone lines, we are doing everything we can to help customers but at this time, we ask customers to keep our telephone lines free for those in difficulty who need our urgent help," Mr Coyle said.
Social distancing measures are all in place in branches.
Advice Centre locations closing temporarily from Friday 27 March:
3 Grafton Street
4 Liffey Valley
8 Swords Pavillion
10 Winthrop Street
Saturday temporary closures, effective immediately (in addition to the advice centres above, except for Ballsbridge, which did not open on Saturday)
1. Athlone (Westmeath)
2. Blanchardstown (Dublin)
4. Castlebar (Mayo)
6. Dooradoyle (Limerick)
7. O'Connell Street (Dublin)
8. Dundalk (Louth)
9. Dundrum (Dublin)
10. Dun Laoghaire (Dublin)
11. Ennis (Clare)
13. Letterkenny (Donegal)
15. Mullingar (Westmeath)
16. Navan (Meath)
18. Tralee (Kerry)