A man and a woman were later being assessed at Hawke's Bay Regional Hospital, media staff confirmed mid-afternoon.
No one was reported injured in another crash in which a vehicle overturned near Eskdale mid-afternoon.
Meanwhile, a man aged in the 40s was in a critical condition in Hawke's Bay Hospital with injuries received in a motorbike crash in Te Awa Ave, Napier, on Sunday morning, and a woman aged in the early 50s was in a stable condition with injuries received when a car crashed on SH38 between Wairoa and Frasertown a few hours later.
The crash happened about 1.55pm and a man was also taken to hospital in Hastings but was discharged after treatment.
The national Christmas-New Year holiday road toll by late afternoon was five, the latest having happened in a crash south of Dunedin about 1pm.
Authorities were still hopeful the period could end on Thursday morning with the lowest in the 61 years for which statistics are available.
The lowest was the six in the 2012-2013 holiday period, there were 12 in the 2017-2018 holiday period and 19 in the holiday period 12 months earlier.
The annual toll for 2018 was 376, with authorities also hopeful the final toll would be less than the 378 recorded in 2017.
The Hawke's Bay toll for the year remained at 19, the most recent more than two months ago and none having been within the official holiday road toll periods of Easter, Queen's Birthday or Labour Day weekends, or Christmas New Year.
The first fatality of the current holiday period was that of 17-year-old Felix Newton after a ute he was driving crashed into the Whanganui River early on Christmas Day.
In other crashes, Indian national Kusum Sarin, 63, was killed when two cars collided at an intersection near Palmerston North's Milson Airport about 12.35pm on Friday, Gareth John Root, 35, of Blenheim, died after the vehicle he was in crashed into Ōpaoa River, Blenheim, early on Saturday morning, and a 25-year-old motorcyclist was killed soon afterwards in a collision with a car reported to have been travelling the wrong way on SH1 near Johnsonville.