Met Eireann has issued a 24-hour rainfall warning for Dublin.
The yellow alert which started at 9am also affects counties Carlow, Kilkenny, Wexford, Cork, Kerry, Tipperary and Waterford.
Up to 35 millimeters of rain are expected to fall, turning heaviest on high ground.
The Taoiseach will meet with Ministers today to discuss the impact of storm Frank and there will also be a briefing from the Government's flood task force.
Jim Casey from the Office of Public Works is warning that the River Shannon is continuing to rise:
