He did not know the cause of the crash.
In a separate crash, a car and a truck collided on Auckland's Southern Motorway near Ōtāhuhu.
The NZ Transport Agency said the crash happened about 6.20am at the top of the Princes St northbound on-ramp and was restricting access to the motorway in both directions, but has now been cleared.
In another early morning crash today, one person suffered serious injuries when the car they were in smashed into a fence in Cambridge.
St John said two ambulance vehicles were sent to the scene about 6.30am.
One person was taken to Waikato Hospital in a serious condition.