Cannabis decriminalisation could happen through a citizen-initiated referendum, says reform advocate Helen Kelly.

At a public meeting at Auckland's Town Hall last night on the effects of cannabis law, Ms Kelly said she hoped a referendum could be pushed through by a dedicated team of volunteers.

About 60 people were at the launch of the "Let's Start The Conversation" campaign, which also featured AUT professor and cannabis legalisation advocate Max Abbott, and Warren Young of the New Zealand Law Commission.

Ms Kelly, who has lung cancer, maintains cannabis is the best drug available to help ease her pain.


"I think we could pull it off if we had the team to do the work," the former trade unionist said of a referendum.

"It's my view we need 500 volunteers getting 800 signatures each [from members of the public]."

While she conceded that was a big job, Ms Kelly said she believed the public support for change was out there and she felt optimistic about the possibility for legalisation.

Dr Abbott said 75 per cent of Kiwi adults were in favour of legalising marijuana for medical use.