The Princes Highway is closed in both directions at Milton due to a truck crash and wires down at Slaughterhouse Road.
Light vehicles in both directions are being diverted via Matron Porter Drive and Bishop Drive.
Heavy vehicles are currently being parked.
Motorists in both directions are urged to allow plenty of extra travel time through the area.
Motorists should also follow the directions of emergency services and traffic crews on site.
For the latest traffic information, visit www.livetraffic.com or download the Live Traffic NSW app.