Cannabis campaigners say the medicinal benefits of the drug are many - and that's why they came to a conference for GPs in Rotorua.

Tadhg Stopford, a legalise cannabis campaigner, spoke at length with doctors from across the North Island on the subject.

"People who suffer from chronic conditions, rely on hippies and other sick people to risk their freedom, growing cannabis, to make compounds for people to heal themselves - I don't think this is acceptable."

Other prominent researchers, Dr Ben Jansen and Dr Graham Gulbransen, gave talks on the subject to doctors and specialists.

Mr Stopford says it's time for the truth around the medical benefits of raw dietary cannabis to come out.

"They are therapeutic, they are non-toxic. You'd need to eat 750 kilograms of cannabis in 15 minutes to die."

Mr Stopford says hundreds were gathering at their stall.

"We are slowly, slowly, slowly making progress. The great opportunity for us here is to develop a therapeutic model of cannabinoid use - research, development, application. The great danger is that, instead, we will end up with a psychotropic, commercialised market that completely removes the health potential."

But that didn't stop him from coming across medical professionals with a difference of opinion.

He says the culture around smoking cannabis - which activates the psychoactive THC compound within the plant - is overshadowing the health benefits found in the plant compound CBD, or cannabidiol.

"Raw cannabis is not psychoactive. There is 0% THC in raw dietary cannabis. You can see the astounding array of therapeutic qualities - anti-cancer, anti-psychotic, bone growth stimulant. Why aren't we feeding our bones, feeding our body?"

Mr Stopford has created a political party, the Farm Cannabis Party of New Zealand, to raise the profile of the debate in the upcoming election.