Christmas bubbles should be as small as possible, and people in Northern Ireland should consider forming them for 25 December only amid an "aggressive new strain" of Covid-19.
First Minister Arlene Foster, deputy First Minister Michelle O'Neill and Health Minister Robin Swann met with chief medical officer Michael McBride and chief scientific adviser Professor Ian Young on Saturday as rules were tightened in other parts of the UK.
Prime Minister Boris Johnson effectively cancelled Christmas for millions of people across London and south-east England after scientists said a new coronavirus variant is spreading more rapidly.
Ms O'Neill said: "Christmas bubbling arrangements are in place for those who feel they need to come together.
Deputy First Minster Michelle O'Neill
"If you must avail of them, then please consider doing so for one day only, Christmas Day.
"Keep your bubble as small as possible and meet for the shortest amount of time you can.
"We are clearly very worried about the Covid-19 situation that is unfolding. The speed at which this variant strain of the virus is spreading is deeply concerning."
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Yesterday, Northern Ireland's Department of Health confirmed another 17 people with Covid-19 had died in a 24-hour period, bringing the death toll to 1,183.
A further 640 new cases of the virus were also reported in the region. There were 427 patients with Covid-19 in hospitals, including 30 in ICU.
Mrs Foster said: "Progression of a new variant strain of Covid-19 in England is concerning, and a reminder to us all to be on our guard to the dangers of the virus.
"The Executive has already taken significant action earlier this week in advance of other regions.
"It is incumbent on us all to do what we can to minimise the risks of Coronavirus spreading.
"We ask everyone to think carefully about all their actions and follow the public health advice rigorously."
The Northern Ireland Executive decided last week to impose a six-week lockdown from 26 December.
But, under current plans, up to three households will be allowed to congregate together in "social bubbles" between 23 and 27 December, unlike the rest of the UK.
The first week of the measures will see the toughest lockdown yet in Northern Ireland, with a form of curfew in operation from 8pm, shops closed from that time and all indoor and outdoor gatherings prohibited until 6am.