The Taoiseach says he is concerned about the omicron COVID-19 variant and its potential spread here.
He says the public's action in cancelling events in recent weeks has resulted in the stabilisation of hospital numbers and intensive care numbers.
Micheál Martin says that will give the health service some headroom in the coming weeks.
However, the Taoiseach says we need more data and science on the variant.
He said: "I am concerned about the Omicron variant, in terms of the high volume that may emerge here post-Christmas or over the next couple of weeks.
"Its doubling time seems to be shorter, and certainly it seems to have an advantage over Delta."
The Taoiseach says the big issue is still whether or not the variant leads to severe disease.
Meanwhile, new data from the UK shows Omicron is "growing rapidly in all regions of England".
The UK's Health Security Agency says it could become the dominant strain in the UK by mid-December - with a warning the UK could exceed one million infections by the end of the month if the situation doesn't change.
However, they say early research shows booster shots of vaccines appear to be very effective - 70% to 75% - in protecting against symptomatic infection from Omicron.
Dr Mary Ramsay said: "These early estimates should be treated with caution but they indicate that a few months after the second jab, there is a greater risk of catching the Omicron variant compared to Delta strain.
"The data suggests this risk is significantly reduced following a booster vaccine."
So far, six cases of Omicron have been confirmed in Ireland.
Nearly 450 new cases of the strain were reported in the UK on Friday alone.
The Government here is now advising anyone arriving from Britain to take daily antigen tests for five days after arrival.