A prominent anti-cannabis campaigner has thrown his support behind decriminalisation of the popular drug.

But one of the most prominent pro-legalisation voices says decriminalisation won't fix many of the problems caused by prohibition. 

On Friday, the preliminary results of the cannabis referendum were released - showing continued prohibition in front 53 percent to 46, with special votes still to be counted. 

Auckland Councillor Efeso Collins of the Manukau ward told NZME the close result "shows there is a very clear mandate for decriminalisation".

"I think the [legalisation] question was a bit extreme and ended up dividing New Zealanders... [Decriminalisation] is a good starting point, and what I think the referendum should have been more focused on."

Under decriminalisation, users wouldn't face charges - but it would still be illegal to manufacture and supply. 

"Decriminalisation is simply about removing criminal penalties from people who use the substance - it doesn't deal with the issue of supply," Green MP Chlöe Swarbrick told Newshub Nation on Saturday.

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"The issue of supply remains one of the biggest potential harms in terms of the opportunity for people to graduate or escalate to harsher substances, get bound up in the criminal justice system - and the potential perverse incentives you create when you decriminalise something and don't deal with that supply chain."

Swarbrick said the fight to reform New Zealand's drug laws is "not over", despite the setback. She's also holding out hope the specials - which typically favour the Greens - will tip the result. One poll showed 97 percent of Green voters intended to vote for legalisation.

"You can't discount half a million New Zealanders - we do still have those specials to come through."

Justice Minister Andrew Little estimates around 70 percent of special votes would have to be for legalisation if the result is going to change - the exact percentage depends on how many special votes there are. 

"It is a longshot, but nonetheless there is potential here," said Swarbrick.

"It's also really important to note how far the dialogue that we're having around drug harm reduction in this country has progressed. It has been light years evolved from where we were three-odd years ago."

She sarcastically congratulated opponents of legalisation, turning to the camera and saying, "Well done - it still exists".