Should medical cannabis be allowed to be grown in New Zealand? We look at both sides of the fence.

With its profile rising and as more people look to alternative treatments for health problems, the horticulture industry sees medical cannabis cultivation as a sustainable business opportunity in New Zealand.

Currently, the cultivation of cannabis for any reason is illegal in New Zealand. Cannabis is classified as a class C drug under the Misuse of Drugs Act 1975 and cultivation is a criminal offence carrying with it a liability for imprisonment for up to eight years.

However, medical cannabis products may be legally prescribed by doctors with ministerial approval. Ministerial approval is rarely granted, but when it is, the medical cannabis products imported will be manufactured from plants grown overseas.

There is an opportunity to legally cultivate cannabis for medical and scientific purposes, and therefore open up a new business opportunity for farmers.

For example, in Colorado State the industry is worth about $1 billion to the state, and generated $135 million in tax revenue.

Legalising the cultivation of cannabis for medical and scientific purposes in strict, closely monitored conditions would not relax New Zealand's stance on recreational cannabis use. It would remain illegal to deal cannabis for recreational use, and those seeking approval to use medical cannabis products would still need ministerial approval.

Cultivation of medical cannabis has been legalised in a number of US states and in Canada. Recently, the Australian Government has announced it will present law changes making it legal for medical cannabis to be grown in Australia.

Legalising medical cannabis cultivation would allow farmers to take advantage of an industry that is growing internationally and to contribute to international supply, potentially creating a much needed diversification in farm export products.

On the other hand, there is little scientific and medical evidence to support the medical use of cannabis and cannabis derived products. While there is some, mainly anecdotal, evidence of medical cannabis assisting medical problems, there remain several risks and side effects.

The cannabis plant is complicated, containing up to 80 cannabinoids and other compounds. Each may have positive or negative medical effects. Because of the number of different compounds, it is difficult to know what cannabis related medicines will work, without negative side effects. Until we do, there is little point in approving large scale commercial growing for medicinal purposes.

In the event that medicinal cannabis cultivation is legalised, farmers should be cautious about converting part or all of their farms. While the Minister of Health has the power to authorise cannabis-based medicines, there have been few applications and fewer approvals. Demand remains low.

Meanwhile, authorised growing operations would necessarily be heavily regulated to ensure the cannabis grown is not misused for recreational purposes, and does not compromise safety. The costs of regulation could likely outweigh the revenue benefits to farmers.

Meanwhile, any cultivation remains illegal. But shouldn't we be having the debate?

Lawyers and legal executives from Auld Brewer Mazengarb & McEwen write about legal topics affecting farmers. The content of this article is necessarily general and readers should seek specific advice and not rely solely on what is written here. Those who would like further information on any topic should contact Auld Brewer Mazengarb & McEwen. This column was prepared by Phil McCarthy who can be contacted by emailing philip.mccarthy@abmm.co.nz