The Glenshane Pass and other routes could be "impassable" in icy conditions on Wednesday night and Thursday morning, motorists have been warned amid ongoing industrial action by road workers.
The Met Office has issued a warning covering all of Northern Ireland about snow for both Thursday and Friday, with freezing temperatures predicted to last until the weekend.
At the same time, workers in Northern Ireland's Roads Service are taking part in industrial action that will limit the salting of the road network.
