On Monday afternoon a person died and another was left with moderate injuries following a single-vehicle crash on State Highway 1, Kekerengu.
Earlier in the weekend a person died in a car crash in the Lower Hutt suburb of Taitā, another person died in Waikato on Saturday morning and one person lost their life following a single-vehicle crash on State Highway 35 about 6km north of Waihau Bay.
There were also many serious collisions across the country.
An eyewitness to a shocking Pohuehue crash yesterday afternoon said the vehicle was driving up a hill "very fast" before it swerved off the road, missing the car in front by "inches".
Michael Agamalis was driving in the opposite direction down the hill on State Highway 1 with his family when he said the vehicle hit an embankment and flipped.
"There was a lady and a kid, in the car in front of him, and what this guy's done, he pulled to the left. And I just heard the crunch as the front of his car hit the dirt and we saw him hit and [the car] spiralled like a bullet coming out of a barrel.
"It launched the car, it got air to the point where its engine went high-rev and that's all you could hear and then you could just hear the crunching and the rolling of the car."
He told the Herald there was no smoke, fire or fuel spillage that he could see.
"The front of the car where the front windshield was, was just crumbled in."
Agamalis, who was driving back to Auckland, said if the vehicle had turned right instead of left he would have been hit "head-on".
"That's how close we were, like he was on our right side and we saw him."
A spokesperson said Auckland Westpac Rescue Helicopter assisted a man, believed to be in his 50s, at 12.41pm after his car plummeted down a 300m bank and through Manuka trees just north of Puhoi.
"He was extracted from the vehicle and carried up the hill by fire and emergency with St John also assisting. He was flown to Auckland City Hospital in a critical condition," the spokesperson said.
The crash caused extensive traffic delays, with cars backed up southbound to Dome Valley, about 14km north of the crash, and northbound delays stretching back to the Johnstones Hill Tunnels.
Traffic was gridlocked for 15km between Puhoi and Warkworth, with Google maps warning of an hour-plus delay for motorists travelling on this stretch of highway.
There was also Northbound congestion on State Highway 1 Bombay to Manukau as Auckland holidaymakers journeyed home.
In Christchurch a person was left in critical condition on Saturday after a fleeing, stolen car carrying four children aged between 10 and 15 struck another vehicle, then collided with a power pole and post box.
The serious crash happened about 3.30am in Linwood where the critically injured victim was ejected from the car.
Superintendent Lane Todd said the driver collided with another motorist at the intersection of Stanmore Rd and Gloucester St, before striking a power pole and a post box.
"While the teenage driver and back-seat passengers, aged 10 and 13, were uninjured, a 15-year-old front-seat passenger was critically injured after being ejected from the vehicle."
The sole occupant of the second car was uninjured.
Also in Canterbury two motorcyclists were injured on Monday following a collision on West Coast Rd, Castle Hill, in Selwyn.
One rider is currently in a moderate condition and the other in a moderate to serious condition.
Over the weekend many Kiwis were able to enjoy plenty of sun, which will extend into the week.
Auckland is set for fine weather today and tomorrow with some isolated showers.