Medicinal cannabis farms are sprouting up around Australia, with demand for the product ramping up in spite of some doctors warning the drug is "not the cure-all" many believe it to be.

Key points: As many as 100,000 people are estimated to buy medicinal cannabis on the black market

As many as 100,000 people are estimated to buy medicinal cannabis on the black market Nearly all medicinal cannabis in Australia is imported, making it expensive

Nearly all medicinal cannabis in Australia is imported, making it expensive Victoria has ambitions the industry will employ 500 people as legal use of the drug increases

Authorities have only granted 3,200 approvals for the legal use of the medicine in two-and-a-half decades, but with 2,500 of those coming last year, the sector is forecasting a year of big growth.

And with more countries legalising medicinal cannabis in recent years, figures in the growing industry say access to export markets will play a key role in establishing the local industry.

Medical cannabis is not approved by the nation's Therapeutic Goods Administration, but can be accessed through the Special Access Scheme, which authorises approved doctors to prescribe the drug.

Trials of the drug are underway in Australia, and have the backing of the Australian Medical Association (AMA).

"Let's look at where it has a role to play," AMA president Tony Bartone said.

"It's not a panacea, it's not going to be the cure-all that some people think it will be, [but] we need to understand what its potential role is."

Advocates are hoping use of the drug will become more widespread, and businesses are investing in growing and producing medical cannabis, pinning their hopes on a surge in the trade.

As many as 100,000 people are estimated to buy medicinal cannabis on the black market, and the potential legal market could be many times that.

Australian manufacturers use imported cannabis oil to produce pharmaceutical products for Australian patients in secure laboratories. ( Image supplied: AusCann )

Business is not only eyeing off domestic use but also foreign markets, with Thailand joining the list of countries legalising medical cannabis.

Analyst Matthijs Smith predicts 2019 will be a big year for the local industry, with Australia well placed to capitalise on global and local interest.

"Australia has been producing botanical-based medicines in the form of opioids for many years," Mr Smith said.

"In fact, we are the leading exporters of medical opioids, and I think we can translate that experience into the medical cannabis scene.

"There are over 100,000 people in Australia currently using medical cannabis for genuine medical purposes.

"My personal view is that is an underestimate of the potential market, which I think is probably more like 250,000 to 500,000 people."

CannGroup chief executive Peter Crock said access to export markets was important while Australian regulations were still restricted and developed.

"We don't have enough demand [locally] and it would be too difficult to set up a new industry with such a low patient base,'' he said.

"But it will change quicker with access to more product — that's why exports are so important."

'The costs are so staggering'

Nearly all medicinal cannabis in Australia is imported, making access to the drug prohibitive for many struggling families.

But local businesses like Cannatrek are aiming to make the product more affordable.

There are plans to build a medicinal cannabis green house facility in Shepparton this year. ( ABC News: Simon Winter )

The company is currently suppling medical cannabis from Canadian sources, and has set up a research facility in Brisbane.

It will begin to build a 160,000-square-metre greenhouse facility in Shepparton later this year, creating 65 jobs, and chief executive Tommy Huppert believes the industry can create thousands of jobs across Australia.

"The idea is that we will be able to manufacture, cultivate and produce affordable medicines to the patients," Mr Huppert said.

"It could well be up to 20 per cent of pain management medicines, so that is quite significant.

"We understand from initial data there are currently over 100,000 eligible patients for cannabis medicines in Australia."

The Victorian Government has been involved in the research and development of the local industry, and has ambitions to be the cannabis bowl of Australia with a target of 500 local jobs.

"We are renowned for our agricultural products, but we are also a gateway to Asia," Victorian Agriculture Minister Jaclyn Symes said.

"This is a very exciting industry. They are all moving here because they see the opportunity that is on our doorstep."

CannGroup chief executive Peter Crock says it is important for Australian producers to have access to export markets while domestic regulations remain restrictive. ( ABC News: Simon Winter )

Another cannabis business, Cronos, is also setting up its headquarters in Melbourne.

Federal Health Minister Greg Hunt told Four Corners last year that Australian businesses would have to guarantee first access to Australian patients as a condition of an export licence.

Sydney mum Jo Freeman is a fierce advocate for medicinal cannabis.

Her six-year-old son Cooper has not suffered a major epileptic fit since he began taking cannabis oil nearly 12 months ago.

"You will never ever be able to put into words what it means for us,'' Ms Freeman said.

Ms Freeman said she was fortunate to find a doctor to help her get cannabis legally, but admits to buying unapproved product from "Nimbin people" in the past in a desperate bid to help her son.

She wants access broadened and governments to assist with costs, with some people spending tens of thousands of dollars.

"The costs are so staggering that for the average person it is just unachievable," she said.

Inquiries from parents of epileptic children about medicinal cannabis happens nearly every day, Epilepsy Action Australia chief executive Carol Ireland said.

The Victorian Government, led by Daniel Andrews, has ambitions to be the cannabis bowl of Australia. ( Facebook: Daniel Andrews )

She said cannabis was a promising treatment option for the 250,000 people in Australia diagnosed with epilepsy, especially for the third that did not get seizure control with currently available and approved anti-epileptic medications.

But she said the challenges were significant.

"Many doctors are still very reluctant to prescribe cannabis or they are unclear about how to navigate the processes the government have established," Ms Ireland said.

"When they do get a prescription, costs can be astronomical.

"We have heard ranges of $35,000 to $50,000 for paediatric epilepsy, unless the child is one of the few who gets on to a clinical trial."