Northern Ireland will be forced back into lockdown for around six weeks from Boxing Day.
Ministers have signed off on an intense period of restrictions after Christmas, with closures of non-essential shops, hospitality - except for takeaways - and close contact services such as beauty salons.
The measures are set to be reviewed after four weeks.
UK-wide rules allowing families to form Christmas bubbles of up to three households are still allowed to go ahead.
Deputy First Minister Michelle O'Neill said the coronavirus situation was "quite dire".
"It's very clear from the positive cases we are seeing every day that an urgent intervention was required," she said.
The tougher rules for Northern Ireland come after Wales also announced it would go into lockdown after the five-day exemption period ends on December 28.
Boris Johnson refused to bow to growing pressure to tear up the Christmas rules as medics warned the easing of restrictions over the festive period could lead to more deaths.
But he urged people to have a "merry little Christmas" by keeping visits short, small and local.
Families across the UK are being urged to think carefully about the risks of travelling to see loved ones and to only stay overnight or see elderly relatives if it is absolutely essential.
The latest restrictions for Northern Ireland come as case numbers continue to rise despite the latest two-week circuit-breaker.
Health chiefs have blamed low compliance with the rules for infections, hospital admissions and death rates remaining relatively high.
Hospitals across the region are running over capacity with occupancy rates at 104%.
On Thursday, Northern Ireland had a further 12 coronavirus deaths, bringing the region's toll to 1,154.
Another 656 new cases of the virus were notified, while figures indicated pressure remained high on hospitals with 460 Covid-19 patients, including 32 in intensive care.
