The Department of Health has issued a warning to "elderly and vulnerable" people living in Kildare, Laois and Offaly.
The caution comes after 226 cases were notified in these counties over the past 14 days - most of which have been linked to clusters.
They also accounted for 49 of 69 new infections reported on Thursday evening.
And the Department of Health has urged those who previously 'cocooned' to limit their interactions with others.
In a tweet, they said: "For those aged 70+ and the medically vulnerable, it is strongly recommended that if you live in Kildare, Laois or Offaly, you should limit the number of people you meet to a very small network, for short periods of time and remain physically distant."
Meanwhile, Ireland's top public health experts are meeting to discuss further measures for the three counties.
NPHET has not ruled out some form of localised lockdown following a surge in new Covid-19 infections.
Acting Chief Medical Officer Dr Ronan Glynn revealed another 60 cases linked to the outbreaks are expected to be confirmed on Friday evening.
He issued an appeal to people in the counties to be on alert for the symptoms of the virus and said NPHET has directly contacted GPs in the area.
He said last night: "NPHET has been informed of a significant number of additional cases across the counties of Kildare and Laois and Offaly on the back of an already significant number of cases and clusters in these counties.
“Over the past 14 days 226 cases have arisen in Kildare, Laois and Offaly, almost half of all cases in Ireland over that time period.
“We will continue to review the situation very closely. However, we are now advising everyone in Kildare, Laois and Offaly to pay particular attention to any new symptoms they may have.
“People in this region should double down on the public health behaviours. Always keep a distance of two metres from other people, do not go into crowded spaces, wash your hands and wear a face covering where necessary.”
