The new 8pm curfew for bars, restaurants and live events comes into force tonight.
The closing time applies to all hospitality venues, as well as cinemas, theatres and other indoor events.
Meanwhile, all indoor events happening before 8pm are limited to 50% capacity or 1,000 people, whichever is lower. Outdoor events are limited to 50% or 5,000 people.
The restrictions are due to remain in place until the end of January.
The Vintners Federation of Ireland CEO Padraig Cribben told Newstalk businesses will be devastated by the rules.
“The nuclear button for our industry was pressed on Friday,” he said.
“Over half the businesses or thereabouts wouldn’t normally open until 5pm in the evening anyway so they are not going to open for a period between 5pm and 8pm.
“It might be fine for those that have a lunch trade or an early breakfast trade but for those depending on the early evening trade the nuclear button was pressed on Friday.”
He said the COVID Restrictions Support Scheme (CRSS) must now be revamped to support businesses that are not reopening and those that “are going to open on a very restricted basis with very restricted turnover and basically, in an unviable situation “.
He noted that the restrictions will have knock-on effects for many other businesses.
“It has a significant effect on entertainment people whether they be DJs or musicians or security companies – so it is right across the board,” he said.
“They are grappling to try and make the necessary arrangements and unfortunately most of the necessary arrangements mean cancelling orders.”
Last night, there were 5,124 new cases announced as health officials said the Omicron variant accounted for around 52% of Ireland’s cases.
The Chief Medical Officer Dr Tony Holohan said the strain had become dominant in Ireland in just two weeks and said it is “extremely important we do everything we can to flatten the curve”.
He urged people to get their booster “at the earliest opportunity”, reduce social contacts and follow basic public health measures.