Ireland recorded 429 new cases of Covid-19 on Sunday.
Tragically, one more person died after contracting the deadly virus.
The latest figures were released in a statement by the National Public Health Emergency Team (NPHET).
Sadly, anyone who contracted the virus since Friday will have to spend Christmas in quarantine.
Of those to be diagnosed in the past 24 hours, 230 were women and 198 were men, 66% of who were under the age of 45.
The average age of those infected was 34.
Dublin saw a large spike, recording 122 new cases.
Donegal also saw a big jump to 46, while Limerick had 30.
The number of patients in hospital battling the virus is up again to 193, while 31 people are in intensive care units.
There were 13 additional hospitalisations in the past 24 hours.
Chief Medical Officer, Dr Tony Holohan, said: "Today, I am concerned that we are seeing the incidence of COVID-19 rising again. 429 is a large number of cases by the standard of recent weeks and the five day moving average has now increased above 300 per day.
“Our efforts in Level 5 in recent weeks brought the 14-day incidence rate down to 78 per 100,000 population, put us in a position of having the lowest disease incidence in Europe and ultimately protected many people and saved many lives.
“Take today’s figures as a sign that we all must now reduce our social contacts, limit our interactions with those outside our households, weigh the risks of what socialising we are planning over the next two weeks, so that we can all have as safe a Christmas as possible.”
The news comes as Ireland wraps up its second weekend since lockdown lifted at the start of the month.
Pubs serving food, restaurants, cafes, retail stores, hairdressers, barbers, cinemas and gyms all returned last week.
And from next weekend, the country will see live audiences allowed back in certain theatres on a trial basis.
