The Labour-led Government is being urged to extend a legal defence for medical cannabis to non-terminal patients and people growing cannabis for pain relief.
As it stands, a law change before Parliament will ensure that patients with less than 12 months to live will not be prosecuted for having illicit cannabis.
Public hearings began on the bill today, and several submitters told the health committee that it did not go far enough.
New Zealand Drug Foundation executive director Ross Bell said the exemption should be extended to patients with "severe and debilitating conditions".
"In reality, terminal patients aren't getting arrested by police, but many other patients are.
"And the way that police are using their discretion means that a lot of people are getting prosecuted still."
People providing or growing cannabis to patients, known as "Green Fairies", should also be exempted, Bell said.
"I know that causes anxiety amongst politicians … but in the real world right now people are growing cannabis and using it for medical purposes and so we think the bill should make legal what is already happening."
Parliament voted down a bill in January which would have allowed people with chronic conditions like epilepsy to legally use cannabis. The bill in Green MP Chloe Swarbrick's name would also have allowed anyone with a prescription to use, possess and grow cannabis to treat a qualifying medical condition or nominate someone to grow cannabis for them.
Swarbrick, appearing before the committee today, said she did not want to re-litigate her failed bill.
But she said that until an official Government scheme for medical cannabis was set up, it was difficult for terminal patients to access medical cannabis legally if they could not grow their own.
"I think we are all aware of the gaping black hole that presently exists. I am aware that my bill was evidently voted down because people were concerned about the so-called 'grow your own' provision, but what we have right here is people still needing to get access to cannabis illegally.
"Otherwise law-abiding citizens are risking jail time in order to provide medicinal cannabis to people in their community for no reason other than to alleviate suffering."
Health Minister David Clark has previously ruled out a broader exemption for growers or patients' supporters, saying that it would "greatly widen" the scope of the bill.
"We want to keep the scope narrow, as it's intended as a compassionate measure until the scheme is established."
Labour's law change will eventually create a medical cannabis scheme which will allow patients to get products from the pharmacy with a prescription from their GP. It is likely to be at least two years until the scheme is in place.
The Royal New Zealand College of General Practitioners medical director Richard Medlicott said his organisation's 4000 members had not considered whether a broader range of patients should get access to medical cannabis.
But he said that if the defence was broadened, the best system would be to create a register of chronic conditions which would qualify for medical cannabis.