Mr Campion's comments come after the tragic case of retired Tauranga aged care nurse Maureen Davies who died in January after her vehicle was rear-ended by a driver high on P.
On October 15 Janine Elizabeth Carter, 37, admitted a charge of driving with evidence of a controlled drug - P and codeine - causing death, which carries a maximum penalty of 10 years' prison or a $20,000 fine.
Mrs Davies, 69, who had recently retired as a registered nurse, was returning home to Hamilton after a luncheon in Tauranga with some former nursing colleagues on January 30 when the crash happened.
She had come to a stop at a set of road works on State Highway 1 at Karapiro, south of Cambridge, when Carter, who was weaving between lanes, crashed into the back of Mrs Davies' vehicle.
Mrs Davies was taken to Waikato Hospital but died from her injures - which included 12 broken ribs - two days later.
Carter suffered minor injuries.
When interviewed by police on April 15, Carter admitted she had smoked P while in Tauranga but could not remember the journey from Tauranga to the crash scene.
Mr Campion said Mrs Davies' death was a tragedy waiting to happen, and preventable.
Mrs Davies' heartbroken husband Stan Davies, 83, said they had been married for 19 years, and his life would never be the same again.
"Maureen was one of the most lovely people you would ever wish to meet.
"She nursed for over 50 years, she was district nurse in Beachlands [East Auckland] that's how we met. She was taking care of me."
Mr Davies said he told his wife to "drive carefully" as she headed to Tauranga for lunch.
"I said it to the wrong person, didn't I?" he said.
Carter, the caregiver of her 2-year-old granddaughter, was also not wearing her required correcting driving lenses.
She will be sentenced in February.
By the numbers
The number of drug-impaired driver offences in the Western Bay region:
2009: 12
2010: 28
2011: 36
2012: 19
2013: 17
2014: 15
2015: 8*
(* as at June 30, 2015)
- New Zealand Police