Dave has been growing cannabis since he was 14 years old, when he began using it to treat his ADHD. Known in his part of New Zealand as a “green fairy”– someone who grows and supplies cannabis to patients suffering from pain and disability – he estimates he has supplied more than 1,000 people over the last decade.

With a few hundred plants on the go, the 33-year-old says what was once a hobby has morphed into a full-time occupation, mostly avoiding the attention of police.

“I have been doing it a long time and I have learned how to do it as carefully as possible,” he says.

But with a referendum on recreational use of cannabis looming next year, Dave might not have to be careful for much longer. He is one of several New Zealand growers preparing for a possible yes result by starting to emerge from the shadowy black market to share their expertise.

Last year the government announced an informal “amnesty” for growers to come forward and work with research and development companies. Now a nationwide search is under way for unique strains of the cannabis plant, with many varieties growing in isolation for decades on the fertile North and South Islands.

Late last year the coalition government passed an amendment to the misuse of drugs act that set out steps to legalise the consumption, cultivation and selling of cannabis for medicinal purposes over the coming years. A legalised cannabis industry is expected to generate up to NZ$240m in tax revenue alone.

‘Mostly good blokes’

The legalisation of both medicinal and recreational cannabis is being seen as a potential boon for marginalised Māori communities in particular, who have seen scores of young men and women imprisoned in regions where employment opportunities are scarce and the drug trade has become a way of life.

The Hikurangi Cannabis Company, which is based in the east coast region of the North Island, has held a series of hui (meetings) with local people to develop agreements that will pay royalties to breeders who contribute strains that realise commercial value.

A cannabis flower Photograph: Supplied, Helius

“There are plenty of growers in New Zealand, most with recently imported strains – but we are interested in connecting with the older breeders who have decades of experience,” says Hikurangi operations manager Panapa Ehau.

“We want to make sure breeders who contribute genetics into the legal industry get ongoing benefit from the knowledge, skills and expertise they have applied to plant breeding.”

Helius is the largest New Zealand company to be granted a research and development licence for medicinal cannabis.

Paul Manning, the company’s executive director, says the majority of the 500 growers who responded to the company’s public callout are men aged in their late 30s and 40s, and most of them are “ordinary Kiwis, mostly good blokes” with no connection to the criminal underworld.

“Its an incredibly exciting time and this industry is moving out of the shadows into a legitimate market place. For some growers that is really scary but others are seeing it as a huge opportunity,” says Manning.

“Its very difficult to get to the bottom of what’s out there in New Zealand. Most of these growers aren’t having their products lab-tested, so most of it is word of mouth.”

Manning believes there may be several phenotype expressions of cannabis in New Zealand, and local varieties of the plant imported from the Netherlands 20 years ago that are no longer widely available anywhere else in the world.

‘Out of the shadows’

According to the health ministry, 11% of New Zealanders use cannabis at least once a year and 44% of those people report using it for medicinal purposes.

Green party MP Chlöe Swarbrick has been a staunch campaigner for the legalisation of recreational cannabis, and says the referendum is well overdue.

“The appetite across the coalition [government] is for a localised market that does not glamorise the substance, but moves the trade from the shadows into the light where we can address potential harms,” says Swarbrick.

“Legal regulation poses the opportunity to allow those who’ve been marginalised… to engage in legal trade, and for those with dependency issues to receive help. Aotearoa New Zealand will not replace the black market with an unbridled free market, but instead create harm-reduction regulation.”

Dave says he thought about quitting the industry years ago after a serious run-in with police, but now so many people are dependent on him, meaning that shutting up shop is no longer an option.

“I want to carry on doing what I am doing, but I want to do it above board,” he says.

“I hate the fact I have to break the law to do what I do but I feel it is necessary to do my job. I can’t stop helping. When you’ve got people that depend on your medicine to survive then things really change.”

After an initial surge of support for the yes vote, polls are now showing voters swinging towards the no camp as rhetoric from the opposition National party ramps up, and conservative lobby groups voice dire warnings.

Polling done by Helius suggests the referendum will be “no slam dunk” for the yes vote, and Manning says his confidence in the vote passing has begun to wane.

“I would like to see the referendum pass, a regulated market is going to offer so many more opportunities for quality control and tax standards than a market dominated by criminals. But I think its going to be very tight.”