Light snowfall and icy conditions in parts of the country have left roads in a treacherous condition, motorists have been warned.
Conditions were bad in parts of Dublin, Kildare, Wicklow, Cavan, Carlow, Tipperary and Wexford, with road temperatures below zero on most routes, AA Roadwatch said.
The motoring organisation urged motorists to drive with extra care, slow down and keep a safe distance from the vehicle in front.
In Wicklow, gardaí have urged motorists to avoid the Sally Gap.
The Road Safety Authority (RSA) received a weather warning from Met Éireann advising of a cold spell this weekend and into the early days of next week.
"This will bring showers of sleet and snow in many areas. The northern half of the country and western counties are most at risk. There will be widespread severe frosts leading to icy roads," the RSA said.
The authority warned road users to be "extra alert" and said greater levels of observation, anticipation and concentration are required when driving in snow or icy conditions.
Minister for Transport Noel Dempsey also urged the public to take extra precautions when travelling on roads during the current cold snap.
Mr Dempsey said: “I urge everyone to be extra alert when using our roads. Remember; other roads users may not expect you, so slow down, be alert and always expect the unexpected when driving, cycling or walking.”
AA Roadwatch said the company’s breakdown service received over 120 calls before 10am today
A number of flights into Dublin airport were delayed for a short time this morning, while Gatwick airport was forced to close a runway. The airport has now reopened. Passengers were advised to contact airlines for further information.
Meanwhile, in Galway, the opening of the M6 motorway will take place at 11am and the road will be open to the public by 3pm. Some 56km of dual carriageway will be opened between Galway and Ballinasloe.
Met Éireann said scattered wintry showers will continue to parts of east Leinster this morning. It will be mostly dry elsewhere with sunny spells after a frosty start. Highest temperatures will be just 1 to 4 degrees.