There were several witnesses to the incident, Senior Sergeant Steve Dickson said.
A lightweight van which had been parked on the side of the road was towed away at about 5.30pm. It is believed it was taken for a forensic examination.
The road was blocked between Clapham and Abbey Cave Rds for three hours while a scene examination was carried out by the Serious Crash Unit.
Police advised motorists needing to travel further east to use the Abbey Caves Rd, from where they could turn right on to Whareora Rd.
Earlier in the day, a man who was riding a motorcycle was taken to Whangārei Hospital with serious head injuries after a collision with another vehicle.
Emergency services were called to a central street in Whangārei after a serious crash involving a motorbike and vehicle. Photo/ John Stone
Emergency services were called to the crash on Central Ave near First Ave about 1.15pm.
Streets around the crash location were shut down as police examined the scene, collecting evidence that would help them piece together what had happened.
Due to the serious injuries suffered by the man the police Serious Crash Unit would investigate.
The motorcyclist was wearing a helmet, Dickson said.
Three occupants in the car received minor injuries.
Dickson said they would be offered help through Victim Support, as would family members of the injured man.
Both the motorcycle and the car were towed away to a secure location and would be subject to a forensic examination.
Central Ave was closed at the intersection of Maunu Rd and Water St and at Second Ave until they were reopened about 3.30pm.
