A leading health expert says people who take risks at Christmas could be 'burying friends and relations in January'.
Dr Gabriel Scally has also said people should not travel home from abroad this year.
He told The Hard Shoulder people should celebrate differently to stop the spread of coronavirus.
"Christmas is so important is so many ways, especially after the year we've had of it.
"It is an opportunity and it's a time for bringing people together.
"I live in England now, but I used to love Christmas in Ireland - Christmas in Belfast was fantastic.
"The whole run up to it I particularly loved, but not this year.
"We've learned to do things differently this year, so we've got to carry that through to Christmas Day and the days around it.
"I think the way in which we traditionally spend time with groups of people - fantastically sociable, a lot of drink, a lot of food - mostly inside, well we've got to do it differently.
"We've got to make sure the virus doesn't spread - it means smaller numbers, doing what you can electronically.
"And I wouldn't encourage people to come back from abroad and be travelling this year - just for this year.
"And I think we should spend more of the time outdoors if we can, if the weather allows us.
"A lot of people go for a walk on St Stephen's Day, and maybe meet people outdoors, arrange to meet them outdoors.
"Do things outdoors: if you're lucky enough to have a garden, plant your Christmas tree in the garden maybe and spend a bit of time outdoors if you can.
"It's the safest thing to do."
"We don't want to have a merry Christmas and then be burying friends and relations in January and February.
"So you've really got to take care".
Earlier Transport Minister Eamon Ryan said while he does not believe normal volumes of people will travel home for Christmas, there will not be a ban on travelling.
While last week Tánaiste Leo Varadkar told the Dáil it is too early for people to book flights home without knowing what the coronavirus restrictions will be.
"I think in terms of people booking flights for Christmas to come home, I'd advise them not to do that at the moment.
"I know that's difficult, I know that's tough but Christmas is six weeks away - and it's too soon now I think for people to be booking flights to come home", Mr Varadkar said.
While Chief Medical Officer Dr Tony Holohan has previously suggested that international travel could be riskier in the weeks before Christmas than it is now.
"The level of disease transmission in this country is improving at a point when the vast majority of countries in Europe are disimproving", he said.
Referring to the EU traffic light travel system, he added: "If I was to guess I'd say there probably won't be many countries on 'green' by the time we're talking about Christmas flights.
"I think it'll be difficult for very many countries to be anything other than 'red' at that point in time".