Motorists are being warned to take extreme care on the roads this morning with overnight frosty conditions adding to problem caused by flooding.

Counties Dublin, Kildare, Carlow, Laois, Wicklow and Meath are the worst affected with black ice reported in many parts.

Overnight frost has already caused several crashes countrywide this morning.

In Dublin, the Clonee Road out of Lucan has been closed because of a multi-car collision while traffic is being diverted on the Malahide road after a truck jack-knifed near Campions pub.

Elsewhere there are at least four crashes on the M7 Portlaoise/Naas Rd and in Cork gardaí are dealing with a seven-car collision on the N8 Cork/Dublin Rd at Watergrasshill.

Gardasí are also warning of black ice in parts of north and west Dublin, Cork, Mayo and Donegal.

There is flooding on roads in Kildare and the Strawberry Beds in Lucan in Dublin are impassable where the River Liffey burst its banks.

Dr Aidan Nulty of Met Eireann says the icy conditions are likely to persist for some time

"Air temperatures fell to a little below freezing and ground temperatures are lower still," Dr Nulty said.

"So with those damp roads frost and ice is a problem this morning and will be for a few hours."