A nationwide Status Yellow snow ice warning has been extended until Sunday.
Met Eireann now says the weather will continue to be very cold until Sunday with severe frosts at night and ice on untreated surfaces.
Treacherous weather conditions are expected in parts of the country over the next few hours, with temperatures falling to as low as -6C tonight in places.
The national forecaster predicts there will be further wintry falls this evening, mainly in the south and east of the country.
Staying very cold and blustery with outbreaks of rain, sleet and snow. The snow will occur mainly inland and over high ground giving accumulations. Falls of snow are possible more widely overnight with severe frost and icy patches. pic.twitter.com/XJNZwcVIlP— Met Éireann (@MetEireann) January 31, 2019
Meteorologist Joanna Donnelly outlined the worst affected areas, saying: "I think the south of the country has been worst affected in the last 24 hours, the north was affected earlier in the week.
"I think the south and south-east are most likely looking at the most severe accumulations of snow."
Dublin Fire Brigade has reported at least a dozen calls for its ambulances to treat people who have slipped or fallen today in the cold conditions.
Our ambulances have received 11 calls for falls since 7 am this morning. Icy conditions on roads & paths so take care if :
🚸 Walking to school
🚘 Driving, esp high groundJanuary 31, 2019
Brian Farrell from the Road Safety Authority said road conditions could be treacherous.
Mr Farrell said: "The main roads and the primary roads are the ones that are going to be gritted, the back roads are the ones that are less likely to be gritted so stay on the main roads, if you can, and avoid the local roads.
"Watch out for black ice, expect the unexpected, slow down, that's the message that we really want to get out to people and stay in touch with the traffic and weather reports in your area."
He also said pedestrians need to exercise caution.
Mr Farrell said: "Really be careful when you are walking on footpaths. The most obvious danger is actually closest to home. It is when you are getting in and out of the car when you are going out the front door and turning onto the footpath.
"Emergency departments tell us that they do get an influx of people coming in with fractures and breaks of arms and wrists from falls in this kind of weather."