A motorcyclist is critically hurt after crashing into a fence on State Highway 2 at Mangatawhiri, in Waikato.
The crash happened near the intersection with the highway and Mangatawhiri Rd, around 12.30pm.
St John says one person has been taken to Waikato Hospital in a critical condition.
State Highway 2 is now open to one lane but there is congestion.
The NZ Transport Agency is urging drivers to follow the instructions of emergency services and watch their speed.