The other deaths also involved farm vehicles and are being investigated.
WorkSafe head of general inspectorate Jo Pugh said the deaths were preventable.
"It's been an absolute tragic start for us in New Zealand this year. The sad thing is this is the time of year when we are meant to be enjoying the summer".
As a nation, she said we were "very slow in our maturity towards risk assessment".
"We don't really think about the risks and don't think they will happen to us".
Pugh said the country needed to change the way it viewed health and safety.
It's seen as a "compliance issue or a payment issue".
"We need to move away from that. Health and safety is actually about caring about people and thinking wisely about the risks you might be facing and then putting steps in place to manage that" Pugh said.
There were many good practical things people could do to prevent injuries and death, she said.
"Make sure you use the right vehicle for the task. Install crush protection devices on quad bikes, make sure you wear your seatbelt and if you're on a quad or motorbike - wear a helmet - and never let children be in charge of an adult vehicle".
Six deaths in eight days
• January 3: One killed after side-by-side vehicle (utility vehicle) crashed at Tamahere, near Hamilton.
•January 4: Chilean student Rocio Atencio Salazar (19), died in a crash on a rural property near Ashburton.
•January 6: A person died in a quad bike accident in Ohakune in the central North Island.
•January 8: Man dies after tractor rolls in Kawarau Gorge, near Cromwell.
•January 9: Tree falls on person at Raukumara forestry block near Gisborne.
•January 10: Quad bike crash on a Wharepuhunga farm, south of Cambridge.
- RNZ
