Tanaiste Leo Varadkar has said that a decision on further restrictions in border counties could be made as soon as today.
The Fine Gael leader said any measures would be influenced by an announcement expected on new restrictions in Northern Ireland later.
Donegal, Cavan and Monaghan are the three counties in danger of a move to Level Four after a surge in new cases over the last few days.
Health officials are set to meet tomorrow to review the situation, but Mr Varadkar said a decision could be made today on any new restrictions that will be made in this area.
He told Pat Kenny on Newstalk: "I haven’t heard yet what the announcement is from Stormont.
"Once we find out for sure what the Northern Ireland Executive has decided, Government will then respond to that and we will see whether we need to take similar measures or what actions we need to take in relation to the border counties.
"We do out best to align and cooperate with Northern Ireland as best we can but, as you know, the Northern Ireland Executive has not favoured an all-island approach or a 32-county approach but we do our best to coordinate and cooperate as much as we possibly can.
"As your listeners will know, the incidence of the virus in Donegal, Cavan and Monaghan in particular is very, very high.
"We will have to make a decision probably sometime today as to whether we need to respond with increased measures in the border counties as well."
Earlier, the Tanaiste confirmed the three counties at highest risk, and also played down suggestions that schools could shut.
He told RTE Radio: "The main reasons why restrictions in the border counties might be tightened is not just what is happening in the North, it's the incidence in those counties which is the highest in the country - Donegal, Cavan, Monaghan.
"We will need to respond to what's happening in the North as best we can."
Mr Varadkar added that "what's in our plan is that the schools stay open".
