There have been 183 new cases of Covid-19 and six deaths reported to the National Public Health Emergency Team (Nphet).
However, deputy chief medical officer Dr Ronan Glynn said an IT issue may have resulted in up to 100 cases going unrecorded overnight.
Of today's cases, 82 were men, 101 were women and 60 per cent were under the age of 45.
There were 56 cases recorded in Dublin, 26 in Donegal, 13 in Limerick, 11 in Kilkenny and 11 in Monaghan.
The remaining 66 cases were recorded across 15 additional counties.
In the North, 456 new cases were recorded today, with 11 additional Covid-related deaths.
Earlier, HSE chief executive Paul Reid said Ireland can expect to start its vaccination programme in early January once approval from the European Medicines Agency (EMA) is obtained.
Speaking at the HSE's weekly briefing, Mr Reid said people should keep a “heightened level of guard” while out socialising over the festive season, saying hugging family and friends is an "extreme risk" for the transmission of the virus.
Mr Reid has previously welcomed news regarding the progress with vaccines, but has stressed that the public must continue to adhere to public health measures until an effective vaccine has been approved and widely administered.
The Government is due to decide next week on priority groups who will receive the vaccine first, with chief executive of the Health Products Regulatory Authority, Dr Lorraine Nolan saying the vaccines are of the “exact same standard” of any vaccine already developed.