All southbound lanes along State Highway 1 leading onto the Auckland Harbour Bridge are closed after a van and truck collided this afternoon. 

The crash was about 3.30pm after the Onewa Road off-ramp. 

The van driver has critical injuries. 

Emergency services are at the scene and the Serious Crash Unit has been advised, police said. 

All three south-bound lanes are closed near the crash site. 

Fire and Emergency sent three trucks and are trying to extract one trapped person. 

Traffic is being diverted at the Onewa Road off-ramp, to rejoin State Highway 1 via the Onewa Road on-ramp. 

Police warn commuters should expect delays. 

A St John spokesperson said they were notified at 3.30pm and an ambulance and rapid response vehicle were at the scene. 

MORE TO COME 

Police are in attendance at a serious crash on the Northern Motorway, State Highway 1, near the Onewa Road off-ramp.