Mr Clarke’s wife, Rox Clarke, had melanoma that spread to her brain.

As previously reported, she died surrounded by loved ones in June.

Mr Clarke, of Windale, said his wife used cannabis oil for about a year to deal with the disease and the side effects of radiation and chemotherapy treatment.

He said this eased pain and inflammation, helped her sleep and stimulated appetite.

“People who are suffering should have the choice to use cannabis as a treatment option,” he said.

He said cannabis was an alternative medicine. Given this, he wasn’t surprised that some medical professionals were resistant to it.

“Big pharmaceutical companies pour a lot of money into the medical system and the big question is how much influence does this buy them,” he said.

John Hunter Hospital’s director of the Hunter Integrated Pain Service, Dr Chris Hayes, recently raised concerns about “who might be promoting the agenda of broadening access to cannabis and what might be their motivations, be it financial or otherwise”.

Dr Hayes said the health and research sectors were advising caution on medicinal-cannabis use.

He and colleagues had been surprised by the haste with which medicinal cannabis had been pushed through parliament for legislation.

A spokeswoman for the NSW government’s Centre for Medicinal Cannabis Research and Innovation said the government was doing clinical trials to “develop a better understanding of how cannabis products can provide relief to patients with a range of debilitating or terminal illnesses, to improve their quality of life”.

“NSW is very supportive of the approach taken by the [federal government] to provide a regulatory environment in which cannabis-based products for therapeutic purposes can be grown and manufactured in Australia,” she said.

“Health-care professionals advise that the evidence for the use of different cannabis products is variable and needs to be carefully considered.

“This is an appropriate approach considering that many cannabis products are still undergoing clinical trials in Australia and elsewhere.”

In an opinion piece in the Herald in August, University of Newcastle Professor of Clinical Pharmacology Jennifer Martin raised concerns about the safety of medicinal cannabis.

Professor Martin, who is a physician, said there was “a particular danger of enthusiastic promotion of any unconventional therapy”.

“It may lead to unrealistic hopes,” she wrote.

“Worse, it may divert patients from evidence-based therapies that may have less mystique and glamour, but have been shown to work.”

She added: “We already have safe and effective therapies available, and funded by the taxpayer”.

Professor Martin will study dosage and its link to benefits and side effects in the government’s medicinal cannabis trial at the Calvary Mater Newcastle. Given this, cannabis advocates have questioned whether her article should have been more neutral.

Asked about this, Professor Martin said: “As a clinical pharmacologist, my primary concern with any new medical drug is that it has been shown to be safe and effective and does not cause more harm than good”.

“It is important to understand that the formal evidence for the use of cannabis products as medicine is limited, despite the considerable community interest and anecdotal reports.

“I understand groups within the community hold much hope for this new area of clinical pharmacology and we are privileged to be advancing research in this space.”

Mr Clarke said terminally-ill people who had benefited from cannabis should not be treated with ignorance and contempt.

“Doctors should try to do the best for their patients,” he said.

Too many doctors had a “why we can’t” attitude.

“We want to know what they can do,” he said.

The Baird government’s cannabis trials are for the terminally ill, chemotherapy-related nausea and children with severe and drug-resistant epilepsy.

In addition to the trials, the government recently enabled doctors in NSW to apply to “prescribe a broader range of cannabis-based medicines”.

“People who are seriously ill should be able to access these medicines if they are the most appropriate next step in their treatment,” Premier Mike Baird said.

Charlestown’s Tim Harding said medicinal cannabis should become a well-regulated herbal medicine.

Mr Harding has a daughter named Arielle, who suffers from drug-resistant epilepsy.

“I believe cannabis could help her,” he said.

He said people should be able to buy cannabis in the natural medicine section of pharmacies.

“You shouldn’t need a prescription,” he said.

He said the medicinal-cannabis industry must be regulated “because people need to know what they’re getting”.

“For compassionate access to be a reality, it needs to be consistent, widely available and affordable.”

Part of the problem for people who were trying to access medicinal cannabis for their kids or loved ones was “having to go through illegal channels”.

Mr Harding was concerned that the pharmaceutical industry and medical sector could try to control the medicinal-cannabis market.

“What I see is a pharmaceutical industry trying to prevent people from being able to grow their own medicine,” he said.

“The problem with turning cannabis into another pharmaceutical is it’s not a pharmaceutical. It’s plant-derived.”

The government spokeswoman said NSW was “managing medicinal cannabis within our existing medicines regulatory system, in the same way as any other emerging medicine”.

This would help address “issues about safety, efficacy, dosage and side effects.”