A full Level 5 lockdown is on the cards before the new year, as the Cabinet meets today over "galloping" Covid figures.
The Government is likely to close all non-essential shops and services, reintroduce 5km restrictions, and to extend the UK travel ban.
People may be asked to leave their home only for exercise or essential purposes, although one minister insisted that the prolonged closure of schools had not been considered.
Gyms and other fitness facilities are likely to close.
Meanwhile, full PCR testing of all arriving passengers is likely to be established at ports and airports - even though the land border with the North remains open.
"People have not been following the rules, and the figures are through the roof," said a Government source last night.
A record 1,546 were confirmed Covid-19 cases yesterday, the Department of Health said. This brings the total number of cases in the Republic so far to 88,439.
There were also a further nine deaths, bringing the total number to 2,213.
Last night, the Department of Public Health urged people in one of the country's worst-hit regions to "avoid large social gatherings of any kind for New Year's celebrations".
There have been 800 positive coronavirus cases in Limerick, Clare and north Tipperary combined over the past two weeks, the Department of Health Mid West said.
"We know that the virus has been widely circulating for nearly four weeks in the community, and spreading through these extended social gatherings in the lead up to Christmas.
"However, while we continue to closely monitor the possible impact of Christmas celebrations, we fear that large household gatherings in recent days may have added an extra layer to what is already a complex situation locally," said Dr Mai Mannix, Director of Public Health Mid-West.
An emergency Cabinet meeting has been called for today to discuss the worsening Covid-19 situation.
Ministers and health officials are doubly concerned that a third wave could peak in mid-January when the healthcare system is traditionally under most pressure.
They are also aware that the fall-out from socialising over the Christmas period has yet to play out in the data.
"There have been parties everywhere although obviously the majority of the population is trying to help control the situation," said a source.
"But the figures we are seeing now, while sky high, are from 10 days ago.
"We haven't seen the Christmas figures yet, and we can expect them to be very bad. So the situation is going to get worse before it gets better."
Higher Education Minister Simon Harris warned that New Year's Eve parties must be a 'complete no-no' this year.
"The Government will decide whether to update its decisions, but the advice of the Chief Medical Officer is good enough for me. He has said to us across the last number of days. Please, please reduce your social contacts, and please try and stay at home," he said.
He added it was also "inadvisable" to gather with others outside to see in the new year. "I'm not a doctor, but my very clear understanding of this virus is that the more you congregate with people, the more likely it is to spread," Mr Harris said.
"Our CMO is very concerned about the spread of this virus. I want everyone in this country to have a chance to get the vaccine. And I don't want to be going to the funerals of loved ones in the months of January and February."
Ireland is about to enter a difficult period because of the British variant of the virus, even though vaccinations have begun, he added.
He said he would not be surprised to see 2,000 new daily infections in Ireland before the new year, as predicted before Christmas.
Ministers will now consider a recommendation from Chief Medical Officer Dr Tony Holohan that the toughest measures from last March and April be re-instigated.
The extra controls will be reviewed in tandem with those already planned from December 31 until January 12 next.
But the Government could also signal that it will be in place for an extended level of time, possibly until St Valentine's Day.
Ministers want to buy enough time to get the vaccine rolled out after the first inoculation yesterday.
One predicted the tight restrictions due to come into effect on January 1 would be brought forward by a day to prevent household revelries to mark the new year.
"I think the main issues are whether it all kicks in on the 31st, or on the first, and how long it should all go on for," the minister said.
"No more yo-yo might be best, staying in Level 5 until the most vulnerable in our society receive their vaccines.
"The Government recognises that it will be really hard on people. Jobs will be lost, and it is a dark and depressing time."
Another source said a longer clampdown would be needed to have a hope of containing the explosion of cases since the easing of restrictions on December 1. The travel ban to the UK is to be extended by a week, such is the threat posed by the highly contagious new strain of the virus.
"The best way of guarding against that British variant may be by extending restrictions," admitted Housing Minister Darragh O'Brien.
But Mr O'Brien said that schools will open in January, and that the issue has not been discussed by the Cabinet.