The Green Party securing the Auckland seat was unprecedented - so another upset could be on the cards.
Canada, Uruguay and 11 US states have legalised it in recent years. So how well has it actually worked?
The association now says it's not taking a position.
"A 'no' vote is a vote to continue cannabis' existence in the criminal black market."
The latest Newshub-Reid Research Poll showed the no vote well ahead. What's going on?
NZMA announced they no longer have a position in the upcoming referendum.
The association had previously said it should be decriminalised and treated as a health issue.
He's also fending off "unscientific and rogue" polls showing him third in the running for Northland.
"If they don't turn up then this isn't going to get over the line."