Recent polls on legalising recreational cannabis show support falling for the 'yes' vote, but also a significant number of undecideds who could ultimately swing the September 19 vote.
The 'yes' and 'no' campaigns are pulling together funding and strategies to reach voters - including the roughly 10 per cent of undecided voters - in what is expected to be an intense and potentially ugly campaign.
Both sides are already accusing the other of misinformation and of being in the financial shadow of the other.
The referendum is being held as part of the Labour-Greens confidence and supply agreement, and the Government has released a draft bill detailing what legalisation would look like.
This week two polls - Newshub Reid Research and 1 NEWS Colmar Brunton - both showed 39 per cent support to legalise recreational cannabis use; the 'no' vote had 48 per cent support in the former and 51 per cent support in the latter.
1 News Colmar Brunton has shown 47 per cent support for legalisation in 2017, 46 per cent in 2018, and 43 and 39 per cent in two polls last year, while a Newshub Reid Research poll last year had 42 per cent supporting legalisation.
Polls by Horizon have also seen a decline in support for legalisation, dropping from 60 per cent a year ago to 48 per cent in November.
This morning a UMR survey commissioned by the Helen Clark Foundation, which supports legalisation, showed more support for 'yes' (46 per cent) than for 'no' (44 per cent).
But after being told about controls in the draft legislation - including a purchase age of 20, restrictions on home-grown cannabis and a ban on consumption outside of private homes or specialised cafes - the 'yes' vote lifted to 50 per cent.
The foundation said it showed more support for legalisation when voters were more informed, but Family First national director Bob McCoskrie said it was loaded to ask the same question either side of highlighting the proposed legal framework.
McCoskrie attributed the decline of the 'yes' vote to the strength of the 'no' campaign so far, including a 24-page pamphlet that had been delivered nationwide.



He added that people had mistakenly thought the referendum was about medicinal cannabis, and had changed their minds from 'yes' to 'no' when they realised it was about personal use.
But Drug Foundation executive director Ross Bell said the downward trend in 'yes' support was because of "well-funded and relentless opposition scaremongering".
He has asked supporters to donate funds to the 'yes' campaign, which was putting together a strategy that included billboards, TV advertising and social media.
McCoskrie responded by saying he was giving the public the "facts", adding that he had little faith in the Prime Minister's expert advisory panel, headed by her Chief Science Advisor Professor Juliet Gerrard.
The panel is putting together publicly-available information about the impacts of cannabis use, what changes have occurred overseas, and how applicable that might be in New Zealand.
McCoskrie added that the Drug Foundation was partly Government-funded.
"I wish we had deep pockets," he said.
The 'no' campaign was gathering a coalition of community organisations that included former cops and drug counsellors, educators and business people who would "benefit from legalisation but have kids and don't want to go down this track".

New Zealand Drug Foundation executive director Ross Bell says opponents to legalising cannabis for personal use are well-funded and scaremongering. Photo / Mike Scott
The UMR poll was based on an online survey of a representative sample of 1000 New Zealanders aged 18 and over, with a margin of error of 3.1 per cent.
Respondents were asked if they would vote for or against legalisation of cannabis, and were asked again after being told about measures in the draft bill including a ban on selling cannabis to anyone under 20, a purchase limit of 14 grams, and limits on how much one can grow at home.
Meanw...