Motorists were advised to avoid both areas.
Earlier, police said a person had been seriously injured in a single-vehicle crash north of Auckland.
Emergency crews had rushed to the Leigh Rd scene in Matakana between Quintal and Takatu Rds just after 6pm.
The road was expected to be closed and diversions put in place.
A second serious crash led to a section of SH6 being closed in the South Island.
Police were at the scene of an accident between Leslies and Mt Riley Rds in Okaramio, Marlborough.
A spokesperson said powerlines had been knocked down and were blocking the road. Emergency services were called to the crash about 6pm.
Police advised the road would likely stay closed for some time.
The Serious Crash Unit were examining the scene.