Traffic on the N25 Waterford to Cork road is being diverted at Adamstown just outside Waterford City, following a collision between three articulated lorries.
Gardai are at the scene of the accident, which has completely blocked the road.
Cork-bound traffic is being diverted away from the N25 at the Tramore Rd Cross roundabout onto the Old Kilmeaden Road. Traffic for Waterford is being asked to use the old Carrick-an-Suir Road.