It comes on the same day that the region recorded its highest daily increase in case numbers of coronavirus.
Some 3,231 new cases of the virus were confirmed in the region on Wednesday, a jump from 2,096 cases recorded on Tuesday.
Deputy First Minister Michelle O’Neill said nightclubs will be closed from 6am on December 26.
The move to close nightclubs was agreed at a virtual meeting of the powersharing Executive on Wednesday as ministers discussed how to respond to the Omicron variant.
Dancing will also be prohibited in hospitality venues, but this will not apply to weddings.
First Minister Paul Givan described measures as “proportionate based on where we are today” but added they will be kept under review.
Ms O’Neill said ministers “spent considerable time agreeing a proportionate package of measures based on the best evidence that we have available to us at this time”.
She said they will continue to analyse the data over the Christmas period.
“In the meantime, we are getting on with planning for all eventualities,” she said.
“Central to our ability to respond to the pandemic has been around the availability of money to support individuals and businesses through this very difficult time.
“We will continue to press the Treasury for financial support because that gives us more flexibility in terms of managing the situation as we see fit here, not depending on what happens in England.”
Health Minister Robin Swann said Omicron is now the dominant variant in Northern Ireland.
He said the precautionary approach would have been to impose more restrictions, but said options were “extremely limited” due to the absence of furlough and additional supports.
“I have made clear to ministerial colleagues that we may have to move quickly again in the event of the Covid situation deteriorating again further and additional funding becoming available,” he said.
“That may have to happen in the very near future but I will say again, it is not inevitable.
“So I would encourage everyone still to come forward and get their vaccinations and follow public health guidance.”
The Executive will meet again on December 30.
Ministers also agreed that sporting events can continue with no limits on capacity, while the work from home message will be bolstered and legislation introduced to require social distancing in offices and similar typed workplaces.
Employers will be encouraged to introduce lateral flow testing procedures for people who are still coming into work.
People attending large events will be urged to wear face masks, take lateral flow tests and not car share to or from the venues.
While nightclubs must close, other restrictions are coming into effect on the rest of the hospitality sector. People must remain seated for table service while table numbers will be limited to six.
Dancing will also be prohibited from December 26.
Weddings are exempted from the latest measures.
NI #COVID19 data has been updated:
📊3,231 positive cases and sadly, 3 deaths have been reported in the past 24 hours.
💉3,428,802 vaccines administered in total.
— Department of Health (@healthdpt) December 22, 2021
The jump in infection numbers is the highest increase reported in Northern Ireland for a 24-hour period since Covid reporting began in April 2020.
The figures come amid stark warnings of soaring infection rates when the Omicron variant takes hold in the region.
The death of three patients who had previously tested positive for Covid-19 were also notified by the Department of Health on Wednesday.
On Wednesday morning, there were 261 Covid-positive patients in hospital, of whom 34 were in intensive care.
Meanwhile, pregnant women of all ages, including those aged under 18, are being urged to come forward for vaccination if they have not already done so.
This follows the latest review of evidence by the Joint Committee on Vaccination and Immunisation (JCVI), who now advise that pregnant women of any age should be considered as a clinical risk group and should be prioritised for vaccination.
Pregnant women of any age can receive their vaccination at a Health and Social Care Trust vaccination hub. Information on vaccination clinics is available on Trust websites.
Pregnant women over the age of 18 can also get their vaccination from participating local pharmacies. Information on pharmacy locations