People are being asked to rethink their plans for the Christmas period to protect families and vulnerable loved ones.
The call, from the Chief Medical Officer, comes as the country gets set to move into Level 5 restrictions tomorrow in an effort to curb rising infection rates.
Hotels, gastropubs, hairdressers and beauticians will have to close, while restrictions on household visits and inter-county travel will be phased in from St. Stephen's Day.
970 new cases were recorded yesterday - the highest in almost two months.
348 are in Dublin, 60 in Limerick, 59 in Cork, 59 in Wexford, 55 in Louth, 40 in Galway and the remaining cases are spread across 19 other counties.
Elsewhere across the region there are 9 new cases in Mayo and less than 5 in both Roscommon and Sligo.
Professor of Molecular Virology at Queens University Belfast, Ultan Power, says people travelling from abroad should not be coming home for the holidays.
