AA Roadwatch said the worst affected areas were parts of counties Kildare, Kilkenny and Wicklow, with the roads R115 and R759 in the Wicklow Mountains impassable due to snow fall.
On the roads elsewhere it was ice caused by freezing temperatures overnight that caused problems for commuters, with numerous incidents reported.
The N81 from Dublin south-west and roads in Carlow were reported as being icy, as was the N22 Cork/ Killarney Rd between Macroom and Ballyvourney.
Accidents were reported at Clonakilty Technology Park and the local GAA ground due to ice on the roads, and another accident occurred at nearby Lisselan.
Cork County Council said road crews have been actively treating county roads since last Friday night and this would be continuing with all priority 1 and priority 2 routes in the council’s Winter Service Plan already pre-treated across the county on Saturday and Sunday nights.
It said Mitchelstown, Fermoy and Mallow routes were also treated over the weekend and black ice had been reported in many locations and grit for community use has been provided at specific locations.
Under the council’s Winter Service Plan, all national roads have priority 1 status for salting and gritting, followed by the regional road network and 110,000km of local roads granted priority 2 status.
All other regional roads and a significant amount of local primary roads are priority 3 locations.
Sean O’Neill of the National Roads Authority said there was 200,000 tonnes of both salt and grit available to local authorities should temperatures plummet.