They recommend people not to travel unnecessarily.
Gardaí in the midlands have issued a road safety fog warning.
Laois Offaly Garda are asking people not to make any unnecessary road journeys.
The dense fog is making road conditions dangerous affecting visibility.
They are advising motorists to turn on fog lights on and travel slow, while leaving plenty of room between the next car.
Meanwhile, the M6 is currently closed at Junction 2 eastbound near Kinnegad in Westmeath.
The closure is due to the removal of a large truck from that section with a crane.
The incident occurred yesterday but Gardai were unable to remove the truck due to the heavy fog and had to wait for better visibility.
Gardai in the area believe the issue should be resolved early this afternoon.