Met Éireann has issued an orange rainfall warning for counties Waterford and Cork which is set to last from Thursday and into Friday evening.
Persistent and heavy rain will begin at 4pm on Thursday lasting until 6pm on Friday.
Met Éireann has said that localised flooding, poor visibility and difficult travelling conditions will occur as a result of the heavy rain.
Meanwhile, a yellow rainfall warning has been issued for all of Munster and parts Leinster at the same time.
Carlow, Dublin, Kildare, Kilkenny, Laois, Offaly, Wexford, Wicklow, Kerry, Limerick and Tipperary are set to see heavy rainfall also.
Met Éireann has said: "Persistent and sometimes heavy rain may lead to localised flooding, poor visibility and difficult travelling conditions."