His ''personal'' view was also that medicinal cannabis should ultimately also be made available to people experiencing chronic pain, and not only to the terminally ill.
If the benefits of taking medicinal cannabis in a particular case ''outweigh the risk, then I believe the drug should be used, even in the case of non-terminal patients''.
''The legal availability of cannabis-based medicines (CBMs) to people who are terminally ill and who have chronic pain conditions is a beneficial step in pharmacological therapy.''
Cannabis-based medicines had ''proven medical benefits in pain conditions''.
Such medicines were not ''magic bullets'' but did ''show efficacy in many patients, especially when combined with other prescribed drugs,'' he said in an interview.
Prof Smith is a professor of neuropharmacology at the Otago department of pharmacology and toxicology, is the author of a book titled Cannabis on the Brain, and is a principal researcher at the Brain Research New Zealand Centre of Research Excellence.
People with a prescription will eventually be able to pick up medicinal cannabis from a pharmacy under legislation introduced to Parliament by the Government last week.
The change to the Misuse of Drugs Act would also ensure terminally ill people with less than 12 months to live would not be prosecuted for having illicit cannabis, the Government announced.
Prof Smith found it ''incredibly ironic'' that some health professionals resisted using forms of medicinal cannabis to treat patients, but were comfortable to prescribe stronger opiates.
''If the evidence supports it, there is absolutely no reason why the chemicals in cannabis should not be used for medicinal purposes,'' he said.
Medicinal cannabis was a ''complex'' topic, including the point that taking cannabis through smoking exposed the user to cancer risks.
He ''absolutely'' agreed that a representative of medicinal cannabis users should be included on a planned group to advise the Government over the development of New Zealand-sourced medicinal cannabis supply, and related cannabis policy.
It was ''very easy to underestimate'' the impact that cannabis-based medicines had on people's lives ''if you don't have a chronic pain condition in particular'', Prof Smith said.
''Many people don't realise that their entire lives are changed by these afflictions.
''If someone is not dying, it is easy to underestimate the potential benefit, but living with a poor quality of life does not benefit anyone,'' Prof Smith said.
