Family First fears a push to make medical cannabis more easily obtainable will lead to decriminalising marijuana in New Zealand.
Former union boss Helen Kelly has written poignantly about the battle she and others face to obtain medical cannabis and is calling for a referendum on the issue at the next election.
Family First says groups who want dope legalised are promoting medicinal marijuana, which manipulates society's compassion for people with serious pain and health concerns.
"But marijuana will then be diverted from medical programs to recreational purposes," says Bob McCoskrie, the conservative lobby group's national director.
Ms Kelly was diagnosed with lung cancer in February 2015 and stood down as the boss of the Council of Trade Unions in October.
She has spoken openly about her cancer journey and has said she's been breaking the law by taking cannabis oil to manage pain. She's seeking government permission to use medical cannabis, but says the process is difficult.
"I am taking nothing really that can stop this cancer killing me, and in not too long a timeframe to be brutally honest," she says in a post on the left-wing blog The Standard.
"It is my view that a good cannabis product will help me live the rest of my life in a better situation than I will without it. The fact I can't do that shows the absurdity of the whole regime."
Family First is calling for the expansion of research into the components of the marijuana plant for delivery via non-smoked forms.
It wants an emergency or research program that allows seriously ill patients to obtain non-smoked components of marijuana before final Ministry of Health approval.
The government should also instruct the Ministry of Health to update the prescribing guidelines for pharmaceutically based THC derivative medicines to include Sativex.
The Australian federal government is planning a licensing scheme to allow cultivation and distribution of medical cannabis.
Associate Health Minister Peter Dunne has said the government will not be swayed by "emotional nonsense" colouring calls for wider access to medicinal cannabis.
He has said there had only ever been one application for a dispensation to use cannabis products not registered in New Zealand - for Nelson teenager Alex Renton - which he had approved.