Police received a report that a car had gone off the road. A person was declared dead at the scene.
A second person in the car sustained minor injuries.
Another person died after a serious crash at Matakana Rd, north of Warkworth, about 6pm on Saturday, police said.
The single-vehicle crash occurred between Oak River Dr and Wright Rd, southwest of the Matakana village.
"Sadly, the occupant of the vehicle has since died of their injuries," police said in a statement.
An investigation by the Serious Crash Unit into the circumstances of the crash is ongoing.
And a fourth person died following another serious crash on Teddington Rd in Governors Bay, Canterbury, at 3.55pm on Saturday.
The crash involved a car and a motorcycle and happened between Allandale Lane and Church Lane.
"Sadly, the motorcyclist died at the scene," police said.
The driver of the car was also seriously injured.
Police said a scene examination was carried out by the Serious Crash Unit and an investigation was under way.