Gardaí are asking motorists to stop using satellite navigation systems and GPS guidance on roads they have been diverted onto because of flooding.
They are also pleading with drivers to slow down on roads where flood waters have cleared, as many motorists are still driving too fast to deal with potholes or other debris.
Superintendent John Ferris is from the Garda Press Office.
It comes as more than 400 homes and businesses are without electricity after heavy rain last night.
The ESB says it is working to repair the faults.
A number of flood alerts have also been lifted following the heavy rain overnight.
Up to 25 millimetres was forecast across the country - with counties Cavan, Monaghan, Louth and Meath the worst affected.
Met Éireann says conditions are expected to improve today. However many national and regional roads are still affected by flooding.
Motorists are advised that many routes are still closed due to large amounts of surface water.
However, further rain is set to move in over the country from late Thursday.
The rain forecast across Thursday night | Image: Met Office
Newstalk Breakfast reporter Kieran Cuddihy was in Athlone, Co Westmeath earlier.