Areas affected by heavy flooding in the past few months should be prepared for more flood waters once the snows start to melt. According to Met Eireann, a rain belt is expected to move up from the south-west overnight tonight and into tomorrow.
"We don't want to predict a terrible gloom and doom, but people should be prepared," said Mr John Doyle.
"There is a fair amount of snow, and if it melts as quickly as it should, all that water has to go somewhere. That, plus rain, is a lot of volume of water in a short time."
Towns and regions which have been badly hit by those floods in recent weeks are most at risk from the rain belt which is expected from tonight.
The rain belt will move up gradually from the south-west with short sleet and snow showers, which could wreak more havoc on the roads already covered with snow.
It will bring milder temperatures of C 5 degrees and C.10 degrees. This is in stark contrast to temperatures yesterday evening of minus 4 at Dublin Airport, minus 3 in Mullingar, minus 1 in Birr and minus 3 in Kilkenny.
The persistently low temperatures in the past few days are at least seven or eight degrees below the average for the time of year.
The warmest spot in the country yesterday was Valentia, Co Kerry, which hit a high of 4.5 degrees during the day while Malin Head got to 2.7 degrees.
However, most inland weather stations never moved above freezing because of snow cover on the ground which reflected back all the heat and light.
It will be well into Sunday before the rain belt has crossed the country, but New Year's Day is expected to be another cold day.
Arctic conditions are set to sweep many parts of Britain on New Year's Eve, which could affect millions of revellers hoping to see in 2001 at street parties.
British forecasters issued an early warning of sleet, snow and freezing rain as the cold snap continues with no sign of warmer weather until later on New Year's Day.
Mr Neil Talboys, a senior forecaster with the PA Weather Centre, said: "Wet weather will sweep in from the west on New Year's Eve, in the form of sleet, snow and freezing rain, creating some really hazardous conditions."
Snow is expected on higher ground in Scotland, Wales, Northern Ireland and northern England, with freezing rain in the Midlands and East Anglia. But south-east England is expected to escape the worst of the weather.
Snowfall is expected to turn to rain later on New Year's Day.
