Figures have been released by the CSO.
Kildare, Laois and Offaly made up two thirds of all new cases of Covid-19 in the country last week.
There were 339 cases in the three counties that are currently partly locked down.
According to the CSO, there were 509 new coronavirus cases in the Republic in the week that ended last Friday.
That's an increase of 224 - or 77 per cent - from the previous week.
The median age of new cases last week was 34.
For at least ten weeks in a row, eight counties have had fewer than 10 new cases.
That feat has been achieved for 14 consecutive weeks in Kerry, and 15 successive weeks in Waterford.
The number of people who've died of Covid-19 in the Republic has been below 10 for the past six weeks.
