[23] Approved cannabis-based pharmaceuticals can be prescribed by a specialist doctor, but require patients to meet strict criteria.

[29][30] In May 2020 the final legislation was made available and it was confirmed that the question put to voters would be:[31][32] Do you support the proposed Cannabis Legalisation and Control Bill?

[39] Leading up to the referendum, much media attention was paid to the upcoming vote, and to arguments for and against the legalisation of cannabis in New Zealand.

Proponents of the bill focused largely on the inefficacy of prohibition, and the prevalence of black market cannabis in New Zealand, while opponents argued that the legislation would allow greater access to the drug, especially for children.

[48] Studies conducted by independent consultancy Business and Economic Research Limited indicate the annual tax intake from cannabis, if it was legalised, would be more than $1 billion.

[49] The NZDF suggested that this money could be put into healthcare (including more addiction treatment facilities), schools, education programmes and other infrastructure that will benefit all New Zealanders.

[50][51][52][53] The age at which people start using cannabis is an important factor, and use of the drug can affect brain development in teenagers.

A New Zealand study found that heavy use by teens led to an average loss of eight IQ points between ages 13 and 38.

The group suggested that this would lead to an increase in cannabis use overall, an outcome that is counter to the purpose of the bill: reducing harm.

A succession of clinical studies have found it increases the risk of chronic bronchitis, inflammation of the throat, and impaired immune function.

[61] There were 15 registered promoters for the 2020 General Election and Referendums, two of which were against recreational cannabis: Family First New Zealand and SAM (Smart Approaches to Marijuana) NZ Coalition and 13 were in support.

[66] The New Zealand Medical Association initially announced its opposition to the legislation, although controversy around a lack of membership consultation led the board to retract their public stance.

Dr Emma Clare said many doctors thought the referendum would pass, and so did not speak up about the NZMA's anti legislation stance.

"[72][67][68] While the government claimed to not have a position on the legalisation of cannabis, opponents of the proposed bill criticised government-published information for bias and lobbying for law change.

[73] The New Zealand Medical Journal was critical of the government naming and promoting the proposed bill as planning to "reduce harm", because evidence on outcomes were inconclusive, as legalisation was a still new model.

[79] Much media attention was given to the fact that prime minister Jacinda Ardern would neither endorse, nor reveal her personal stance on the referendum.

In May 2020 Jacinda Ardern polled as New Zealand's most popular prime minister in a century, thanks in part to her success in dealing with the COVID-19 pandemic.

[81][82][83] Ardern stated that she wanted New Zealanders to form their own views on the matter, and that the Labour Party also held no official position.

[84] Professor Papaarangi Reid, head of the department of Māori health at the University of Auckland, suggested the legislation would have helped regulate its strength, its cost and limit its accessibility by young people.

[133][134] Aaron Ironside, spokesperson for SAM-NZ (who endorsed a "No" vote), agreed that Ardern's silence contributed to the result and said she had done the right thing letting voters decide, as that was the point of the referendum.

[135] National MP Nick Smith described the preliminary result as a "victory for common sense" and that New Zealanders had "signalled opposition to the softening of drug crime".

Family First director Bob McCoskrie of the "Say Nope to Dope" campaign said that he was "pretty stoked" with the preliminary referendum results and that New Zealanders "understood the perceived benefits of legalisation were not greater than the harms that were going to come on society".

He said: "Not only is the idea that the electorate should decide any particular issue impracticable, the closeness of the cannabis vote means that the prohibition of the drug is now unworkable" and argued that parliament should, "consider the ethical merits of subjecting the minority of otherwise law-abiding citizens to criminal sanctions for smoking dried leaves at the behest of a puritan majority".

"[137] Victoria University Associate Professor, Dr Fiona Hutton, said she thought the No campaign advertisements were "based on outdated moralised notions of those who use drugs, influenced by rightwing religious groups from the US".

Hutton also thought "the playing field was never level, [and] that absolutely fantastic academics, community groups, organisations and campaigners [...] sought to educate, to inform, to circulate evidence, to give people clear and balanced information, fought to get their voices heard amongst swirling misinformation and misdirection".