Some cycling advocates say making helmets optional would get more people biking and increase public health, but critics say that opens them up for brain trauma.
Cycling Action said yesterday that they agree helmets are the safest option, but want the law reviewed.
Speaking this morning to TVNZ 1's Breakfast programme, Choice Biking's spokesperson Lisa Clist said there are different styles of bike riding, from casual to high speed, and the law doesn't recognise that.
"Sometimes you're going through a park, you're going at jogging speed, but that's illegal (not to wear a helmet)," Ms Clist said
She said cycling rates halved when helmets were made compulsory in New Zealand, and that removing the restriction would get more people "out there being active and healthy".
"There's a simple truth that it just puts some people off," she said.
Ms Clist agreed that it was safer to wear a helmet, but argued that a sedentary lifestyle leading to heart disease was more dangerous.
"What about the longer term health problems in New Zealand?" she said.
"What if there were some amazing activity that you could use to combat that in your daily life - that's cycling."
Figures show 18 people died while riding bikes on New Zealand roads last year, and brain injury specialist Kathryn Jones of the Laura Ferguson Trust says the risk of injury while riding a bike without a helmet is much greater.
"Not wearing a helmet when you're cycling can lead to a far more serious and traumatic brain injury," Ms Jones said.
"Within our serious brain injury unit, about eight per cent of clients that have come through have been cyclists.
"Common sense prevails - if your head hits the pavement at force ... a helmet will provide some protection.
"I would support looking at other alternative ways for getting people on their bike."