The army is en route to Mountmellick in County Laois after heavy rain caused 'unprecedented' flooding in the town.
Around 40 families were forced out of their homes overnight after three local rivers burst their banks.
It followed a day of torrential rain that saw flooding across parts of Munster and Leinster.
Authorities are urging drivers to avoid the County Laois town.
In a statement, the council said: "Members of the public are requested to observe road closure signs, drive appropriately and not attempt to drive through flooded areas."
Teams assisting with the evacuation of people from their homes due to flooding in Mountmellick at the moment. pic.twitter.com/fw3AT4hdFN
— Laois Civil Defence (@LaoisCivilDefen) November 22, 2017
Fire, rescue and emergency services staff from throughout the midlands have been drafted in today as clean-up efforts get underway.
The army has also been mobilised.
Soldiers arrived in Mountmellick this morning to help with the clean up operation, while more are expected throughout the day.
In a statement, the President Michael D. Higgins expressed his "deepest concern and sympathy" for all those affected.
“This will be a devastating experience for them, and I want to thank all those in the state, local authority and voluntary sectors who are coming to their assistance,” he said.
“As events like this are occurring with greater frequency we will be called upon to draw on our resource of solidarity ever more often, and I know the Irish people will recognise and support the importance of good planning and policies that may prevent or mitigate such occurrences.
“On days like today the thoughts of all of us should be with the families affected.”
Laois County council has set up a support centre in the town to help residents affected by the flooding.
Director of Services Kieran Kehoe says their HQ is at Wolftone Court in Mountmellick town:
“It is just around the corner from one of the worst affected areas of the flooding in Mountmellick town,” he said.
“We will have a team of people there along with Department of Social Protection people.
“They will be there for people to call in, address any issues they have; give them any aid or support and help them in or out whatever way we can, whether that is provision of food, provision of blankets or any other support these people may need.”
Padraig Fleming is the Cathaoirleach of Laois County Council:
“There are three major rivers heading towards the Mountmellick town, which is the Barrow, the Owenass and the Blackwater,” he said.
“This has been unprecedented rain that I don’t believe we have experienced before.
“It came in very fast and began then to flow down to the houses.”
He said local services are working hard to help residents, but warned it will “take a few days to assess” what needs to be done to get people back into their homes.
"If the houses are flooded... you know the effect of flooding.
"We've seen it throughout Ireland in various places. It destroys houses."
He said flooding has hit Mountmellick this evening in an "unprecedented way".
Flooding around Co. Laois- all crews currently mobilised. pic.twitter.com/oVg1nyMKBn
— Laois Fire & Rescue (@LaoisFireRescue) November 22, 2017
Wetting the whistle
However, the flooding did not manage to dampen spirits in some corners of the Laois town.
Dowlings pub on O'Moore Street kept its doors open despite having several inches of water on the floor.
Publican Junior Dowling says a bit flooding is not enough to put off his regulars: