Some of New Zealand's top medical experts have come out in favour of a "yes" vote in the upcoming cannabis referendum.
An editorial published in the New Zealand Medical Journal called the Cannabis Legalisation and Control Bill referendum a once-in-a-generation "opportunity to place evidence-informed controls around a substance that is widely used and unregulated".
"A yes vote is not a vote in support of cannabis — it is a vote in support of placing public health controls around a substance that is currently left to the black market to manage," the authors - specialists in addiction treatment, public health, Māori health equity and epidemiology - said.
"If the referendum is successful, it will result in public health legislation with world-leading goals and aspirations that could serve as a model for other countries."
The strong vote of support comes a week after early voting opened for the referendum, and the latest poll showed a slight lead in support.
A Horizon Research poll found 52 per cent of respondents supported the bill and 47 per cent opposed, a slight change from the 49.5 per cent for each recorded in an August poll.
One of the authors, epidemiologist Dr Michael Baker, told the Herald this peer-reviewed editorial - as with all published by the journal - was independent and purely reflected the views of the authors.
It was not a response to the NZMA stance, he said.
"It is purely coincidental - we wrote this about a month ago."
Baker, who is not a member of the NZMA, said he was not sure what evidence they based their stance on and it seemed "unusual for it to take such a definite policy on something like this".
"When the evidence is so compelling for law reform, one thing that tips me in favour is to put the policy on the agenda for the new parliament to look at, to thoroughly debate, rather than just shutting it down.
"Our prohibition model doesn't work. Supporting law reform is about reframing cannabis use as a health issue which opens up new, more effective ways of minimising harms caused by this drug."
Cannabis is New Zealand's most commonly used illicit drug. The latest New Zealand Health Survey figures indicate 15 per cent, or 590,000 adults, used cannabis in the past 12 months.
The editorial - written by Baker, Professor Papaarangi Reid, Professor Louise Signal and Dr Sam McBride - cited the Christchurch longitudinal study, which found 76.7 per cent of participants had tried cannabis by the time they were 25.
They noted use was heaviest in the group aged 15-24, and those aged under 25 were also the group most at risk of adverse health outcomes from cannabis use.
Health harms were experienced predominantly by those who started using young, used heavily and frequently, used high potency products and/or had a history of psychosis in the family.
These were the groups public health interventions should focus on to reduce harm, but prohibition was not adequate to ensure that happened, they said.
They also cited research from the Chief Science Adviser, which found prohibition also did not reduce cannabis use for those caught, noting 95 per cent of those convicted continued to use at the same or an increased level.
"Our cannabis laws are not only ineffective — they are directly harmful to those who fall foul of them," the authors said.
"Several thousand New Zealanders each year receive a conviction for cannabis-related offences, with implications for employment, travel, education, future earnings and mental health.
"More than half of these convictions are for low-level offences such as possession or use of cannabis, and those affected are disproportionately young and/or Māori."
Papaarangi Reid, head of the Department of Māori Health at the University of Auckland, said they were "particularly concerned Māori have borne the brunt of biased enforcement and the negative health effects of illegal cannabis".
Māori are three times more likely to be arrested and convicted of a cannabis-related crime than non-Māori with the same level of use.
Māori are almost twice as likely as non-Māori to go to court over a first offence and nearly seven times more likely to be charged.
They are also more likely to suffer harm from cannabis use and less likely to be able to access health treatment.
"This fall-out from our drug laws is a high and inequitable price to pay for a policy that is not effective at reducing harmful use," they said.
The bill also included mostly civil rather than criminal penalties for breaches, acting more like a speeding ticket.
Regulation would allow for public health interventions, working in a similar manner to tobacco where usage has reduced by half in the past two decades.
Meanwhile, unregulated, yearly cannabis use nearly doubled from 8 per cent to 15 per cent between 2011 and 2019.
The bill also learned from mistakes made with other regulated products, such as not allowing advertisers to saturate airwaves and sports fields with branding.
By legalising, people would be more encouraged to seek help for cannabis-related health issues, a situation particularly dire for Māori.
The bill puts aside a levy from sales to support help-seeking services and a Cannabis Regulatory Authority would be required to develop and implement a harm-reduction strategy covering prevention, education and treatment.
Civil society would also have input through a Cannabis Advisory Committee, a watchdog of the regulatory authority required to include Māori representation.
The authors acknowledged there was a risk of unpredicted outcomes, as with every public health intervention, but continuing with the status quo was not acceptable.
"Responsible legal regulation means tackling harmful use, and reducing the criminal, social and health impacts for Māori.