Health officials in the Republic have urged people to "take care and caution" as the reproductive rate of Covid-19 increased to 1.
The Department of Health in Dublin announced yesterday that a further six people diagnosed with Covid-19 had died.
It brings the total number of deaths there to 1,743.
A further 23 cases of the virus have also been confirmed, bringing the overall number in the Republic to 25,565.
Professor Philip Nolan, chairman of the National Public Health Emergency Team's modelling group, said the Covid-19 reproductive number had increased.
"We are seeing an increase in the number of reported cases over the last two weeks and the R-number is now at or above 1," he said.
"There is an immediate need for all of us to take care and caution in our decisions and actions.
"Broadly speaking, the last couple of weeks we have seen very low levels of the disease and very low case numbers confirmed per day.
"We had a particularly low case count two weeks ago with only 61 cases confirmed that week.
"This increased to 93 the following week, and at the end of the week we will probably see a similar number of cases.
"If you're seeing an increase in cases then you're going to see an increase in the reproduction number.
"We have said before that this estimate is quite unreliable when you have got low numbers and the estimate varies quite widely.
"The reproductive number is now at or just above 1.
"For several weeks we have been looking at reduced disease and the R-number in the region of 0.5."
The Republic's chief medical officer Dr Ronan Glynn expressed concern as all of the 23 confirmed cases of coronavirus reported yesterday are among younger people.
Some 77% of cases reported are under 25 years of age, while all of the cases are in people who are aged under 45 years of age, he said.