Emergency services were expected to be at the scene for quite some time.
A spokesperson said an investigation was under way to determine the cause of the crash.
More FM Northland reported the crash was between a car and a logging truck, between the SH12 intersection at Brynderwyn and Atlas Quarries.
NZTA urged motorists to delay their journey if possible to allow extra time for a detour via Paparoa, which is suitable for heavy vehicles.
St John has been approached for comment.