Six people have died so far during the Bank Holiday weekend in accidents involving cars.
Mr Tim Regan (47), of Ballygarvan, near Cork city, was a passenger in a car on the wharf close to the Haulbowline Naval Service base at Ringaskiddy, Co Cork, when the car left a narrow quayside and went into the water.
It is understood that Naval personnel attempted to free Mr Regan and the car's driver, believed to be his wife - whom the Garda last night refused to name. However, Mr Regan was dead when help arrived.
The driver of the car was comfortable last night at Cork University Hospital.
According to sources, the car was reversing when it went over the quay wall into a particularly deep area.
Another road fatality occurred at Gortroe, Youghal, Co Cork, at 5.30 p.m. on Saturday. Mr John Walshe (43) was killed instantly.
Mr Richard Walsh (23), from Dunboyne, Co Meath, died in a two-car collision between Dunshaughlin and Ratoath on Saturday night. In another two-car collision at Newbawn, between New Ross and Wexford town, on Saturday, Mr Eamonn O'Brassil (60), from Bray, Co Wicklow, died.
Yesterday morning, Mr Anthony Collins (33), from Naul, Co Dublin, was killed when his car and a lorry collided at St Margaret's Road in north Co Dublin.
Meanwhile, gardai last night confirmed that an 80-year-old woman pedestrian was killed in an accident involving a car at Roscommon Road, Athlone. The accident happened at 7.30 p.m. and the woman died at the scene. Her name has not been released until relatives have been contacted.