Delays were expected.
Traffic could be seen building in lanes past the Bader Drive overbridge, with the backlog extending 5.5km to Puhinui Rd.
Police said two northbound lanes were blocked before the Walmsley Rd overbridge and traffic was building.
NZTA said: “Consider using SH1 for northbound travel.”
An NZTA photo showed emergency services at the crash, with a vehicle lodged close to a road barrier.
Photos of the incident seen by the Herald show a small red car parked behind a campervan, which has a Hato Hone St John ambulance parked beside it.
Google Maps shows the traffic stretching back past Wiri, about 7km from the crash site.
A spokesman for Auckland Transport confirmed no public transport services are being impacted by the incident.