Parts of the main Belfast to Londonderry road were flooded
The Department of Regional Development has warned that heavy rain may continue across Northern Ireland until early afternoon.
A DRD spokesperson said there was a danger of flash-flooding and ponding on many roads.
Drivers are advised to allow more time for their journeys and to take extra care on the roads.
There was heavy flooding in the north-west with the road between Londonderry and Limavady badly affected.
It is thought the heavy rain may have been the cause of power failures in Enniskillen and Donaghadee where around 200 homes in total were affected.
NIE said power had now been restored to the area.