More recently however, he said even reluctant cyclists had accepted the law and strapped up.
"I think, over time, it's just become accepted really. I think you'd probably find more people riding with helmets because it is the law, regardless of whether they agree with it.
"We sell quite a lot of helmets to people who say 'Oh I don't really want to wear one, they look stupid, but I have to because it's the law'."
He said most people he saw riding around did wear helmets - mostly for safety.
"We still get a lot of people who say they won't ride on the road ... I hear people say the cycling awareness is not as good in Whangarei as it is maybe in other areas.
"I think people just feel like rather than waiting a little bit of time and passing safely, they just go, because you're 'just a cyclist'," he said.
Nationwide, fines for failing to wear a helmet also halved in the past three years, from 9936 to 4748 last year.
The Cycling Action Network's Patrick Morgan said he believed the fall in helmet infringements seemed to be a result of changing police priorities.
"I think it's just police have better things to do than stop people on bikes and fine them for helmet use or misuse," Mr Morgan said.
"I welcome police resources going into higher priorities."
Mr Morgan maintained that there is "thin" evidence that mandatory helmet use laws work, and that Australia and New Zealand are the only two countries that have such a law.
"There's enough evidence that mandatory bicycle helmets hasn't worked as intended, and that's why it's our policy to review the law, to see if it's working as intended - but it's not our top priority."
He said CAN's position was not a call for making helmets optional, but to review the wider effects of helmet-wearing legislation.
Mr Morgan said he doesn't normally wear a helmet when cycling on the road. He has a legal exemption - on medical grounds as he said helmets gave him headaches and migraines. He said he was stopped three or four times per year.
"I wear it if I do something dangerous, like mountain biking or something risky like that. But [not if I'm] just riding around my neighbourhood or on a separate New Zealand cycle trail."
Superintendent Stephen Greally said safety on the road was a priority for police, whether the road user was in a car, on a bike, or using some other form of transport.
"There has been no change in the way police enforce laws for bicycle related offences," he said.
"When an officer attends a job, they are responsible to assessing the situation and providing an appropriate response to ensure the safety of the public.
"The response from an officer could range from an infringement notice to a warning or prevention advice, this decision is made at the officer's discretion."
