Government ministers are restricting their movements after a Cabinet member tested positive for Covid-19.
Agriculture Minister Charlie McConalogue received a positive test result earlier today.
A spokesman for the minister said he is not displaying symptoms.
Mr McConalogue, who attended a Cabinet meeting on Tuesday in Dublin Castle, recently travelled back from Brussels from an EU meeting on fisheries.
As an essential worker he was not required to self-isolate on his return but he did have to undergo a series of Covid tests.
It is understood the minister tested negative before leaving for Brussels and again on his immediate return. His positive test was returned after he undertook a required follow-up test on Tuesday.
A spokesman for the minister said: "He is displaying no symptoms and is in good health. He is now self-isolating."
The development came as Ireland prepares to enter fresh lockdown restrictions amid spiralling infection numbers.
Ministers gathered in Dublin on Tuesday to decide the new measures.
Curbs will be phased in over the Christmas period, coming into full effect on January 1. The Government has warned they could be in place for months.
From Christmas Eve, Ireland will start returning to the highest level of its Covid-19 response - Level 5 - with some adjustments, such as allowing shops to remain open.
Ministers are proceeding on the assumption that the new variant of Covid-19 is already circulating in Ireland.
Restaurants and gastro pubs will have to close at 3pm on December 24. Contact services such as hairdressers and beauty salons will also close from Christmas Eve.
Inter-county travel will be prohibited after December 26.
From January 1, no gatherings among households in private homes and gardens will be permitted.
Experts on Ireland's National Public Health Emergency Team (Nphet) have warned that Ireland is in the midst of a third wave of the pandemic.
Case numbers have soared by more than 70% in the last week. On Tuesday, another 13 Covid-19 linked deaths and 970 new confirmed cases of the virus were reported in Ireland.
The current measures that allow visits from two other households to a private dwelling or garden will end on December 27.
One other household will be allowed to visit up to December 31 before a ban on visitors, apart for essential purposes, will come into effect.
The adjustments from full Level 5 include non-essential retail being able to remain open, with guidance that shops do not run January sales.
Gyms, leisure centres and swimming pools could remain open for individual exercise, but no sports matches can take place apart from those at elite level.
Schools will stay open.
After 3pm on Christmas Eve, hotels will only be able to remain open for essential and non-tourism purposes.
Christmas religious services will be allowed to take place but after December 25 services should return to an online format. Places of worship will remain open for private prayer.