Four additional cases of the new variant were confirmed by the Department of Health following further whole genome sequencing of positive cases.
There are 504 Covid-19 patients in hospital today, of which 109 are in ICU.
It comes as Higher and Further Education Minister Simon Harris has said “we should boost the booster campaign” and described the coming weeks as a “race between the Omicron variant and the booster”.
Mr Harris said the Government are in favour or extending the booster campaign to those over 40 but will need to look at ways to “operationalise” this intention.
“Yes, we should boost the booster campaign. Everything that can be done to achieve that will be done.
“We’re on target to have 1.5m people boosted by Christmas, and next week we will see an updated roadmap on boosters published by the Department of Health.
“We are very eager to move ahead with people above the age of 40 but it’s very important that we check how that can be operationalised best.
"We obviously now have plans for a vaccine programme for children, so this is the week we will see an updated plan for the rollout of the booster vaccines.
“I know a lot of people are worried about queues and appointments at the minute so it’s important to bring it back to first principles, and if you are eligible for a booster vaccine at the moment, you will receive an appointment. The walk-in centres are an additional way; we’re opening all channels to try and get as many people boosted between now and Christmas,” Mr Harris said on RTÉ’s This Week In Poltics.
He said the signs were “extremely encouraging” around the protection being afforded against Omicron by the third dose of the vaccine.
Meanwhile earlier today, Professor of Immunology Kingston Mills said that the five-month gap between the second dose and the booster for Covid-19 should be removed.
Prof Mills said that the booster campaign should be expedited in light of recent data on the Omicron variant and the effect the booster has on it.
“Give it to everybody who’s eligible and don’t wait for five months,” Prof Mills said on Brendan O’Connor’s show on RTÉ Radio 1.
“This five months - there is some benefit in having a longer gap but this is offset by the huge benefit of vaccinating everyone now that really need the protection,”.
Prof Mills referenced the latest results of a UK study that three doses of a vaccine give over 70pc protection against symptomatic Covid-19 from Omicron, while two doses offered far less protection.
The Trinity College immunologist said that Omicron is likely to be the dominant variant in the UK in the coming weeks, and added: “if it happens in the UK it will happen in Ireland too”.
This may take a few weeks longer in Ireland as it appears it is not as widespread here yet, the professor suggested.
He predicted Omicron may be dominant here in January.
“We’ve had a very small number of cases [of Omicron] so far, and if we could manage to contain those, we could avert the worst effects of it. This will depend on how well we can contain it. The problem is we’re so linked to the UK and Northern Ireland by travel that it will be difficult to stop it,” Prof Mills said.
The five antigen test requirement for arrivals from the UK is a “very good” infection control measure if people comply, Prof Mills said, adding “it’s very difficult to enforce it”.
There have been just six cases of the new variant found in Ireland across three counties but public health officials have indicated they expect many more in the coming days and weeks, and expect it to overtake Delta and become the dominant variant here.
The “bright thing” is that a lot of our vulnerable populations have had three vaccines, “so hospitalisations should not be high, hopefully”.
Vaccinations will not limit the spread of Covid-19, Prof Mills said, but may be effective in stopping severe disease and hospitalisation.
“It will not limit the spread. The best vaccines now are unlikely to prevent infection with Delta, not to mind Omicron.
"Unfortunately, we’re not going to limit the spread of the virus with the vaccine but the hope is we’ll limit serious disease,” Prof Mills said.