Another new strain of Covid-19 has been identified in the UK, with two new cases involved.
Two cases have been identified that are linked to people who arrived in Britain from South Africa.
Anyone who arrives in the UK from there is being told to quarantine.
The news comes as Government is urging people to reconsider their Christmas plans.
The HSE is warning the risk posed by the virus is at its highest point to date.
Anyone who has plans to visit older people specifically is being asked to think twice.
The Republic faces fresh lockdown measures from Christmas Eve amid fears the new variant of coronavirus is a factor in spiralling infection rates.
Taoiseach Micheál Martin said the Government was acting “quickly and aggressively” to try to suppress soaring case numbers.
Tuesday saw 13 more deaths related to Covid-19 recorded in the Republic and an additional 970 cases.
It brings the total number of deaths linked to the virus in the State to 2,171 with 81,228 cases, according to figures from the Department of Health.
There are currently 239 patients in hospital with the virus, with 25 in intensive care units.
The positivity rate among people tested for Covid-19 is now at 4.8 per cent, up from previous weeks, and more than 81,000 tests have been carried out in the State over the past seven days.
The 14-day incidence rate of the disease is 138.2 cases per 100,000 people.
Donegal has the highest county incidence rate at 290.8 cases per 100,000, up from recent days. Leitrim has the lowest rate, at 28.1 cases.
The Mid and East Antrim council district is the worst hit area in the North, with an incidence rate of 540.6 cases per 100,000 people over the last 14 days.
The next highest rate is in the Fermanagh and Omagh area, with 477 cases per 100,000.
On Tuesday another 439 people tested positive for Covid-19 in Northern Ireland and 16 more deaths were reported, according to the region's Department of Health.
The State's chief medical officer Dr Tony Holohan said the current trajectory of the disease in the community was “of grave concern” and warned that inter-generational visiting over Christmas is now extremely risky.
“It is up to each one of us to re-think our plans for this Christmas period, especially when it comes to visiting older or more medically vulnerable family members and friends,” he said.
