They have described driving conditions as “hazardous” on many routes across Northern Ireland due to snow and freezing temperatures.
“Please avoid all unnecessary travel if possible,” said a spokesperson.
“If you must venture out, please reduce your speed and drive to suit the conditions.”
The driving warning comes as the Met Office issued a yellow weather warning for ice across Northern Ireland.
Further wintry showers are forecast for the rest of the evening but they will become fewer and lighter later tonight.
There will be strong northwest winds which will gradually ease.
It will stay cold with a touch of frost in sheltered spots and there will be a minimum temperature of 1 C.
Tomorrow the wintry showers will continue to die out during the morning. It is expected to be dry and bright with sunny spells. It will be another cold day with a frost setting in during the evening.
The Met Office for Northern Ireland says maximum temperature tomorrow is likely to be 5 C.