The Taoiseach has said that the worst of the pandemic "could very well be" in front of us.
Speaking on RTÉ's Brendan O'Connor show, Micheál Martin said that the latest Covid-19 restrictions will be kept under constant review as the Omicron variant spreads across the country.
Mr Martin said "it is never wishful thinking" to hope that things may turn out better than expected.
"There is not an inevitability," he added.
When asked if he thinks that the worst of the pandemic is still in front of us, he said: "It could very well be. Certainly, it's that severity question that is unknown and the data simply isn't there."
Last night, Mr Martin announced that bars, restaurants and other indoor venues must close at 8pm, starting on Monday, until the end of January.
The Cabinet rejected a recommendation from NPHET to close pubs and restaurants at 5pm.
Capacity limits for indoor and outdoor venues were also announced, as were changes about the restriction of movements for people who are close contacts of confirmed Covid cases.
Mr Martin said that he was not fully surprised by a recommendation to close hospitality by 5pm. However, he said he felt that it was too early.
He also said that antigen tests should be done more routinely, and that he was an "early believer" in the testing.
But he said that he is not in favour of giving them out freely in a wide way, adding that at the moment around 100,000 antigen tests are being given out free for close contacts.
In relation to vaccines, the Taoiseach said that Ireland will need to establish "independent vaccination capacity".
When asked if a permanent team of vaccinators needs to be in place going into the future, he said: "We are going to have to work on that, yes."
Martin 'very worried' about Omicron variant
The World Health Organization has said the Omicron variant of Covid-19 is spreading significantly faster than the Delta strain in countries with documented community transmission.
It said the variant has a doubling time of one-and-a-half to three days.
Mr Martin said that how severe the Omicron variant is in terms of requiring hospitalisations, ICUs and damaging people's health remains "the great unknown".
He said that he is "very worried about Omicron".
Mr Martin said that it will take time to understand the full impact of the Omicron variant and the Government cannot wait to see how the situation evolves.
Real damage would be done "if we didn't intervene," he said, adding that people's behaviour will make a difference.
"You know, the combination of behaviour and boosters will matter, yes, in terms of reducing the impact of this. That's the point and that's why we're moving early," he said.
The Taoiseach said that he is "confident" that schools will reopen in January, but said that it will be "challenging".
He said he thinks that there was "a huge problem" after the midterm break in October, adding that NPHET is suggesting that the Halloween break "created a fairly significant rise in cases".
Vaccines will be open to all children aged five to 11 from 10 January, he said.
Mr Martin also said that the Government and NPHET must engage with one another, but also respect the boundaries.
He said: "I genuinely have to say this, because people go on about NPHET-Government tensions and all of that, my view is we've got to engage with each other, but at the same time respect the demarcation lines."
Mr Martin said that he is not a public health expert and that from the outset public health has had to be central to the response to the pandemic.
Sinn Féin health spokesperson David Cullinane has said that the Government cannot say that it has been "caught on the hop".
Speaking on RTÉ's Saturday with Katie Hannon, the Waterford TD said: "I think the frustration is also with Government in relation to the lack of planning and it's a case of 'here we go again'.
The Government cannot continue to say that they are getting caught out and are not thinking about all of the different options and scenarios."
Mr Cullinane said that the Government has known about Omicron for a number of weeks.
"Certainly for those number of weeks there has been a lot of speculation that this is going to be difficult. It was classed as a variant of concern weeks ago," he said.
Nurses concerned over hospital impact
The General Secretary of the Irish Nurses and Midwives Organisation has said that healthcare workers are "very worried about the seriousness of what is facing them".
Speaking on RTÉ's Saturday with Katie Hannon, Phil Ní Sheaghdha said: "I spoke to quite a number of nurses in the last 24 hours saying, I don't think people understand how serious this is.
"One nurse, for example, was standing with a patient who was very breathless in his 30s, not vaccinated, struggling for breath and saying 'I made the wrong decision'. He didn't make it."
She added that some nurses have told her that "the number of beds that are available is nothing like what's been reported by the HSE".
Some patients who should be in ICUs are now in wards because there are not enough beds, she said.
