State Highway 16 east of Waimauku, Auckland, is completely blocked following a head-on crash between a light truck and a car, described by NZTA as "serious".
Police spokesperson Kim Chambers said the crash occurred near the intersection at Cloverfields Drive in Waimauku.
The driver of one of the vehicles was trapped with moderate injuries, but had now been freed.
Police said the driver of the other vehicle had minor injuries.
NZTA warned commuters to expect delays and avoid the area if possible.
Police are diverting traffic at Factory and Foster Roads.