Motorists are advised to drive with extreme care due to freezing conditions and treacherous roads around the country.
Gardaí are urging road users in counties Laois, Offaly, Roscommon Mayo and Galway not to make any unnecessary journeys.
In Galway, icy conditions are affecting a number of roads, including the N6 between Craughwell and Galway.
Gardaí in Laois are advising motorists to avoid the Cut road between Mountrath and Clonaslee.
Ice is affecting the N4 Dublin to Sligo Road between Carrick-on-Shannon and Longford at Aghamore.
Secondary roads in Tipperary should also be avoided and care should be taken on the N25 Cork to Waterford Road as the exit for Youghal is icy.
The N11 road from Bray to Wexford is reported to be extremely dangerous at the moment because of ice.
There have been a number of collisions and an ambulance has overturned near Gorey, Co Wexford.
Meanwhile, gardaí are advising motorists travelling in the Dublin city area to exercise caution on all roads, including major routes into and around the city, due to icy road conditions.
The M1 between junction four in Donabate and junction six in Balbriggan is very icy.
It has not been gritted, and there have been a number of collisions, including a five car crash.
Pedestrians are also being advised to take care. One Dublin hospital - St Vincent's - is reporting an upsurge in the number of people presenting themselves to their A&E department after slipping on ice.
