Severe flooding throughout the south-east made driving conditions extremely hazardous and some roads impassable.
Among the worst affected areas was Clonmel, Co Tipperary, where the quays and other areas became flooded and a number of people were evacuated from their homes.
More than 1,500 sandbags were delivered by Defence Forces personnel to local people earlier yesterday.
Waterford city and south Kilkenny were also very badly hit. A mud slide on the Mullinavat-Waterford road blocked one side of the road and caused serious delays.
A Garda spokesman said many of the approach roads to and from the city were affected and people were being urged not to drive unless necessary.
Flooding on the Cork road at Waterford Crystal led to a number of minor accidents and the road had become impassable, he said. The Tramore road, the Dunmore East road and the Cheekpoint road, at Jack Meade's pub, were also flooded, while the "back road" to Belview Port from Ferrybank was under three feet of water in one place.
A number of trees were blown down in Kilmeaden, and even where there was an absence of flooding, wet leaves on the roads were making driving difficult, he added.
The severe wind and rain had eased by early last night but the incoming tide was expected to bring floods to the quays and other areas of Waterford city.
In Clonmel, emergency services including the Defence Forces, the Garda, Clonmel Corporation and the Irish Red Cross were on 24-hour standby in an operation co-ordinated by the local Civil Defence.
A Civil Defence spokesman, Mr Eddie Cooney, said large-scale evacuations had not yet begun but people who chose to leave their homes were being assisted.
"People with young children, for example, are concerned when they see the water gathering at the door," he said.
There had been flooding in a number of areas of the town and not just those affected on previous occasions, he said. Highfield Grove, where a local stream burst its banks, was one of the many residential areas hit.
Fire brigade units and Civil Defence personnel were called out all over the region to try to alleviate the most severely flooded areas, which included the road between Ballyhale and Mullinavat in south Kilkenny. In New Ross, Co Wexford, a Garda spokesman said many minor roads were impassable.
