A heavy haulage tow truck is heading to a crash in Auckland that's causing traffic chaos.
A truck and trailer unit heading southbound on State Highway One hit the Penrose overbridge at around 11:20am.
All southbound lanes had been blocked, but lanes two and three have reopened.
Southbound traffic is backed up to Fanshawe Street, while northbound traffic is bumper to bumper as far back as Highbrook.
Motorists are being asked to delay their travel.