Heavy rain is expected to sweep across the country on Monday night and into Tuesday, Met Éireann has said.
A level orange rainfall warning will come into effect on Monday at 7pm for Cork, Kerry, and Waterford and will remain in place until 9pm on Tuesday.
Very heavy rain on Monday night and Tuesday will likely cause further river flooding and surface water flooding.
Rainfall totals of 50mm to 80mm are expected and higher in mountainous regions.
Meanwhile, a level yellow rainfall warning will come into effect on Monday at 9pm for Carlow, Cavan, Clare, Dublin, Galway, Kildare, Kilkenny, Leitrim, Laois, Limerick, Longford, Louth, Mayo, Meath, Monaghan, Offaly, Roscommon, Sligo, Westmeath, Wexford, and Wicklow.
Rainfall totals of 30mm to 50mm are expected for these counties and higher in mountainous regions.
The warning will remain in place until 9pm on Tuesday.