NZTA has told drivers to expect delays until congestion eases and traffic flow returns to normal.
Emergency services were at the scene and police said the road needed to be cleared.
Traffic from the crash was backed up to Ōtāhuhu heading north and to Spaghetti Junction heading south. Photo / Google Maps
Hato Hone St John said it was notified at 2.35pm about an incident.
One patient, in a serious condition, was taken to Auckland City Hospital.
Traffic was backed up to Ōtāhuhu on the northbound lane, about 10km from the crash site, while southbound traffic was backed up to Spaghetti Junction, according to data from Google Maps.
NZTA said a journey from Bombay to the city would have taken more than two hours, and a journey in the other direction would take one hour, 13 minutes.