40 Tesco stores around the country are to open for 24 hours in the week leading up to Christmas Day.
The plan is an effort to reduce demand pressures during what will already be a busy week for the chain, made more complicated by the Covid-19 pandemic.
"The safety of colleagues and customers remains our number one priority and we continue to make changes within our stores as we prepare for the Christmas trading period," said Kari Daniels, CEO, Tesco Ireland.
"We hope that these extended hours, up to 24 hours in 40 of our larger stores during Christmas week, will help make the shopping trip easier for our customers."
The additional hours will begin in certain Tesco extra and superstores from Monday December 21, which will open from 7am on a rolling 24-hour basis.
Extended store opening hours will be in place across the entire 151 stores in the Irish network, beginning on Friday December 18.
The majority of those will operate from 7am until midnight, with 40 moving to a 24 hour basis from Monday 21 until 7pm on Christmas eve, the retailer said.
From the 14-17 December, there will be normal opening hours of 7 or 8am until 10 or 11pm.
During Christmas week the company will also give priority access to stores all day to over-65s, family carers and the extremely medically vulnerable.
Staff will be in place to man car parks, external queues and entrances.
The company also said that its stores will be restocked daily or several times a day, with fresh produce.
Customers are also being asked to shop alone where possible, although Tesco says it recognises that this won't always be feasible.
The Tesco Ireland stores rolling out 24 hour shopping between 21 and 24 December are listed below.