A group representing the elderly has appealed to Parliament to be able to grow its own cannabis.

Grey Power's Otamatea branch, from Northland, said older people with "unbearable" conditions should not have to deal with illegal gangs to get cannabis for medical use.

Denying people alternative means of pain relief when traditional medicines did not work was a form of elder abuse, the group's representative Beverley Aldridge told MPs today.

She was appearing before a select committee considering a law change which will exempt people with terminal illnesses – but not chronic conditions - from prosecution if they use medical cannabis.

Aldridge said: "A stroke at our age destroys a couple. The injured partner may go into care, leaving the other floundering and having to also go into care.

"For those who were previously independent souls, life is unbearable. As strokes are common in our age-group we must have the human right to prevent or ease the debilitating effect ... by growing our own cannabis."

Family members had died "screaming in pain" from cancer and other conditions because pharmaceutical drugs had given no relief, she said.

"This is barbaric and … uncivilised. We call it elder abuse.

"We are entitled to live our later years in an optimum of health using whatever plants will aid that. It is our human right to choose our medication."

Grey Power's national association has distanced itself from the Tamatea branch's advocacy for medical cannabis.

Grey Power Otamatea representative Beverley Aldridge says elderly people in chronic pain should be able to grow their own cannabis. (Photo /Northern Advocate)

The New Zealand Medical Association also appeared before the committee this morning.

Chief executive Lesley Clarke said her organisation supported the declassification of cannabinoid (CBD) as a controlled drug, which was also included in the law change.

But it could not support the decriminalisation of medical cannabis for terminal patients, because it did not believe that cannabis met the regulatory test for a medicine.

She said the compassionate exemption for terminally ill cannabis users from prosecution sent an implicit message that cannabis was therapeutic.

"That means that throughout this bill, cannabis is being recognised as a medicine…. We remain of the view that to be considered a pharmacotherapy, cannabis must confirm with other regulated medicines.

"This requires at a minimum delivering the same dose of drug and as noted evidence of efficacy and evidence of safety."

Clarke cited a American Medical Association review of 79 clinical trials of medical cannabis. The review said there was "moderate quality evidence" to support the use of CBD for chronic pain.

There was "low quality evidence" to support the use of cannabis for treating nausea in chemotherapy patients or sleep disorders. The trials also demonstrated a link between CBD and "adverse short-term events".

Clarke said her organisation accepted that it was time-consuming for cannabis products to get approval as medicines, and it supported the introduction in New Zealand of products which had already been given regulatory approval overseas.

NZMA said the process of getting cannabis products approved as medicines was time-consuming and it supported the adoption of products which had already gained approval as medicines overseas.