An Adelaide company is to become the first in South Australia to begin cannabis extractions and create market-ready products from a secret laboratory in the city.

GD Pharma has been importing cannabis components from overseas but under its new manufacturing licence it will be able to import the plants, extract the chemicals, and produce a range of experimental prescription products.

Chief executive Antony Condina said it meant they could control the concentration of cannabis to create tailor-made products for a wide range of clients.

Some 266 patients are approved to use medicinal cannabis Australia-wide.

He said the main hurdle to achieve the manufacturing license was the risk of cannabis being shifted into the black market, including risks of theft and being "held up".

"We had to demonstrate we've got processes on site, and one of those [is] we're not allowed to advertise the manufacture and storage of these compounds."

Media articles earlier this year cited the company's cannabis imports, which Mr Condina said resulted in members of the pubic visiting their Norwood labs to harass the staff and demand to see the plants.

GD Pharma's secret new factory will operate by the end of year and would take about one week to produce a batch of diluted resin that costs about $500 for a bottle.

Mr Condina said they were unlikely to draw a profit because red tape restricted doctors' ability to prescribe cannabis.

"At the moment we haven't seen that much demand," he said.

"Last year it was estimated about 100,000 Australians would benefit from medicinal cannabis but, in reality, there's only been around 100 patients in 11 months who have been approved for products."

Proponents say there is evidence to suggest cannabis products can help with conditions like multiple sclerosis, severe intractable epilepsy in children, intractable nausea and vomiting due to chemotherapy.

Those opposing it, however, along with the Federal Department of Health, have cited a lack of quality research along with ongoing investigations and trials as the reason for restrictions.

Senior lecturer in medicine at Australian National University, Dr David Caldicott, said that only a few clinical trials had been published in English and not a single Australian university had a cannabis-related course.

He said this left doctors cautious about prescribing medication and pharmacists unable to offer counselling.

Dr Caldicott said many "vested interests" like those in the opioid industry were also hampering the industries growth.

"These [proponents] aren't a group of people that are free-loving hippies," he said.

"They're people with long-standing medical problems and the cannabis suits them better, not only in the way it works, but also the absence of side effects."

Dr Caldicott said people interested in its recreational purposes would not look to the pharmaceutical industry for a hit, because it was much easier to buy marijuana through illicit means, and illegal marijuana had a higher concentration of chemicals needed for to get "high".

"It's like saying we shouldn't be using morphine in patients because heroin is bad for you," he said.