People have been urged to be careful around coastal areas and rivers following Storm Emma and heavy snowfall in recent days.
The RNLI and Irish Coast Guard have issued the joint warning as snow and ice begins to melt around the country, bringing a risk of flooding.
The two organisations say that while river levels have remained relatively low, the thawing snow could lead to surges.
Met Éireann is also forecasting strong winds along the east coast.
A status red weather warning has been lifted, but forecasters are still warning of treacherous conditions and a flooding risk.
Owen Medland, RNLI Area Lifesaving Manager, said: "It’s been a tough few days for the country and people will want to get out and about as soon as the weather moderates. Many people rescued by RNLI lifeboat crews had no intention of entering the water in the first place.
"All too often, people’s first instinct when they see someone in trouble in the water is to go in after them. If you see someone in danger, dial 112 and ask for the Coast Guard straight away. Look for a ring buoy or something that floats that they can hold on to and throw it out to them."
Gerard O'Flynn of the Irish Coast Guard added: "Please heed the warnings and be mindful of the risk posed by a surge in river levels following the expected thaw and be mindful of the risks on exposed coastal areas."
The warnings follow an incident yesterday, where passers-by pulled a swimmer to safety from stormy seas at Sandycove in Dublin.