The early closing time of 8pm for all restaurants, bars and cafés has come into effect this evening, as part of new restrictions aimed at curbing the spread of the Omicron variant.
The restriction, which does not apply to takeaway or delivery services, was one of many announced by the Taoiseach on Friday.
Taoiseach Micheál Martin said this will help the country get to the other side of the current wave as safely as possible.
Indoor events scheduled earlier in the day have to limit attendance to 50% of capacity or 1,000 people, whichever is lower.
Outdoor events are also limited to half capacity, to a maximum of 5,000 people.
Wedding receptions can take place after 8pm, but with a capacity limit of 100 guests.
Religious services are exempt from the restrictions.
Enhanced measures also come into play for people deemed close contacts, with those yet to receive a booster vaccine having to restrict their movements for ten days.
Those who are one week since their booster face restricting their movements for five days, and are to take three antigen tests.
The measures will remain in place until 30 January.
CMO appeals for people to 'follow the spirit' of guidelines
Chief Medical Officer Dr Tony Holohan has said the new restrictions will substantially cut the volume of total social contact across society if people follow "not just the letter but the spirit" of the guidelines.
Dr Holohan said "it is now down to people individually" to confine social engagements to small groups of people and not to meet up with multiple groups of people over Christmas time.
Speaking on RTÉ's Morning Ireland, he said people should look to cut out discretionary contacts and that there are no plans to introduce stricter measures before Christmas.
However, he said that NPHET will continue to monitor the situation over Christmas and is available to give more information to the Government if need be.
Chief Medical Officer Dr Tony Holohan has said that NPHET 'aren't going away for Christmas' and will continue to monitor the Covid-19 situation over the festive period | Read more: https://t.co/RwPwO0cqQl pic.twitter.com/CNlwwbgCLa— RTÉ News (@rtenews) December 20, 2021
The CMO met representatives of the arts and entertainment industry this afternoon to speak to them about recent decisions taken around attendance at live entertainment events.
RTÉ News understands that Minister for Arts Catherine Martin had asked Dr Holohan to take part in the online meeting.
Support schemes available to the sector will also be discussed.
Latest coronavirus stories
Couples 'left in purgatory' over wedding guest cap
Meanwhile, Dr Holohan said that the new restrictions are intended to protect against a significant increase in hospitalisations and the wider protection of public health.
They are also in place to protect the country's ability to deliver education, childcare and other essential services, he said.
Ireland is potentially at risk from a major surge of the virus that is now being felt in countries including Norway, Denmark, the Netherlands and the UK, Dr Holohan said.
He said the effects of the Covid-19 vaccines in terms of protection are maintained in the face of the Omicron variant, although NPHET has to monitor how well it holds up.
He said a lot of misinformation is being spread by some in society in relation to vaccines, which is not helpful.
Dr Holohan said if current case numbers were happening a year ago without vaccines, then the situation would be far worse.
The Chief Medical Officer has dismissed 'misinformation' that Covid-19 vaccines 'don't work'.— RTÉ News (@rtenews) December 20, 2021
'If we had these case numbers right now 12 months ago, when we didn't have vaccination, we would have... many, many more deaths,' Dr Tony Holohan said | More: https://t.co/RwPwO0cqQl pic.twitter.com/nYkXB9TU0x
Asked if he had discussed further restrictions with the Taoiseach, Dr Holohan said: "I know there was a report in one of the newspapers yesterday to say there was a firm plan for us to meet on 30 December to announce a lockdown at that point and that we'd already indicated as such to him. That's simply untrue."
Dr Holohan said the Taoiseach himself over the weekend had made it clear that "nothing is ever ruled in", adding that NPHET continues to monitor the effect of measures.
Tánaiste Leo Varadkar said that the Government would be in a position early tomorrow to announce changes to the Covid Restrictions Support Scheme (CRSS).
This scheme is to be relaxed to allow business restricted by Government order - in relation to capacity or operating hours - avail of it.
"They will be getting the kind of financial support both when it comes to wages and overheads that they would have got back in the full lockdown when they were entirely closed," he said.
Tánaiste Leo Varadkar has said he does not foresee a situation where schools do not reopen following the Christmas break in January.— RTÉ News (@rtenews) December 20, 2021
Speaking on @morningireland, Mr Varadkar also said there was 'no case' to close the schools early | Read more: https://t.co/RwPwO0cqQl pic.twitter.com/SjnZfTphm0
Speaking on RTÉ's Morning Ireland, Mr Varadkar also said he does not foresee a situation where schools do not reopen following the Christmas break in January.
He added there was "no case" to close the schools early beforehand.
Tánaiste confident new restrictions will be enough
The Tánaiste has said there is no secret plan for additional restrictions before Christmas, or before the New Year or even in January.
But speaking at the launch of the IDA's annual results today, he said the caveat is that it is not possible to rule anything out in this pandemic.
He said those restrictions coming into effect today will last until 30 January and while the Government cannot rule out being able to ease restrictions earlier, it also cannot rule out having to tighten them if there was a sudden deterioration in the hospitals.
He said he is confident, but not certain, that the new restrictions will be enough.
Mr Varadkar said he thinks there will be some very high case numbers in the coming weeks and they will scare people.
But he added that he does not think they will translate into the levels of hospitalisation and ICU admissions or deaths that may be feared.
However, he said that will not be clear for another few weeks and that is really why the Government has imposed the restrictions as of today.
He also said it is never just about restrictions, and Government imposed restrictions only go so far, and therefore it is about what everyone does as individuals and as families.
"If we all do those things together I think we can weather this wave but it can never be vaccines alone or restrictions alone or masks alone, no one thing on its own will be enough," he said.
Mr Varadkar said the restrictions on hospitality probably do mean more people will socialise at home.
But he said the objective of the restrictions is not to eliminate socialising but to reduce it by around 30%.
On the impact on business, he said the system of supports is very good and has worked very well and compares well internationally.
He said the Government does still intend to phase them out in 2022 if the pandemic allows them to because they cannot last forever.
Mr Varadkar said the Government is always open to ideas from unions and industry bodies but does not want the supports to be around forever.
Additional reporting Sinead Crowley, Will Goodbody