Police say it is too early to speculate on why the road toll for Queen's Birthday weekend spiked this year, to its worst level in 13 years.
Nine people died on the roads during the official holiday period which ended at 6am on Tuesday.
The figure is the worst since 1996 when 10 people were killed during Queen's Birthday weekend.
However, it is still well short of the record of 24 set in 1973.
Inspector Peter McKay says this weekend's toll can only be described as "grim" and it is too early to say what is behind the higher number of road deaths.
He says poor weather probably contributed to the high number of deaths but the various crash investigations are still at an early stage.
Police on Monday confirmed a man involved in a crash near Rangiora in Canterbury died from his injuries.
Meanwhile, an 18-year-old man was discovered dead in his vehicle early on Monday. Police say the man was the sole occupant of the vehicle which collided with a power pole in the Hakataramea Valley in Waitaki.
The driver of a truck and a pedestrian were killed on State Highway 1 at Ohakea about 6am on Sunday.
Another person was killed in a crash on the southern motorway in Auckland about 1am on Sunday.
Four people died after two cars collided on State Highway 30, 11km east of Benneydale on Saturday.
The holiday road toll period began at 4pm on Friday.