Met Éireann has issued a status orange rain warning for Cork and says very heavy rain tonight and Tuesday will likely cause further river flooding and surface water flooding.
The warning will come into effect at 7pm tonight in Cork, Kerry, Tipperary, Waterford.
It will remain in place until 9pm tomorrow night.
The forecaster says that rainfall totals of 50 to 80mm are expected and will be higher in mountainous regions.
A status yellow wind warning also comes into effect in Cork this evening.
Met Éireann says southerly winds will reach mean wind speeds of 50 to 65km/h, with gusts of 90 to 110km/h, possibly higher on exposed coasts.
Where winds are onshore there is a risk of coastal flooding, it said.
The warning will come into effect at 9pm and will remain in place until 6am on Tuesday morning.