Every morning, Brent Arcuri uses a glass pipette to carefully drop a small dose of cannabis oil under his tongue.

Key points: Patients say the way the Federal Government regulates medicinal cannabis has made it prohibitively expensive

Patients say the way the Federal Government regulates medicinal cannabis has made it prohibitively expensive Many Australians are being driven to the black market to access the product

Many Australians are being driven to the black market to access the product There is currently no subsidy for medicinal cannabis under the PBS, but the TGA expects this may change

The 20-year-old from the Gold Coast suffers from Crohn's Disease, an inflammation of the bowel that makes digesting any food a painful chore.

"Every day I wake up I have some sort of pain purely from eating food," Mr Arcuri told 7.30.

"It can cause me to be very fatigued all the time."

After years of trialling various medications with limited success, a friend suggested he try medicinal cannabis.

Last year, Mr Arcuri was prescribed a cannabis oil product from his doctor.

Seeking cannabis oil for medical purposes has been legal since 2016 when federal laws were changed to allow doctors to prescribe cannabis products to patients suffering an array of conditions.

"It's only after you get accepted, they tell you the associated costs," said Mr Arcuri, who was initially paying around $600 a month for medicinal cannabis.

He soon discovered he could buy cannabis oil for roughly a quarter that price on the black market, importing it from a US-based website.

Brent Arcuri uses cannabis oil he bought online in the kitchen of his Gold Coast home. ( ABC News )

There is currently no subsidy for cannabis products under the Pharmaceutical Benefits Scheme (PBS).

Doctors wishing to prescribe it must first apply to the Therapeutic Goods Administration to seek individual patient approval, a time-consuming process that provides further motivation for patients to access cannabis products via illegitimate routes.

But the licensed cannabis industry warns there is no guarantee of purity or safety with black market products.

'We have complete control over the environment'

Fleta Solomon with a worker at her secret cannabis facility south of Perth. ( ABC News: Tom Joyner )

Fleta Solomon runs a pharmaceutical company at a secret facility south of Perth that farms cannabis to make legal medicinal oil, one of the first of its kind in Australia.

"In comparison to growing in a backyard, we have complete control over the environment," Ms Solomon said.

This ensures product consistency and allows growers to continually test the plants for contaminants, bacteria and mould.

The strict regulations that Ms Solomon's company must adhere to, combined with higher production costs, means their product is more expensive than those available on the black market.

John Skerritt believes medicinal cannabis could eventually be listed under the PBS ( ABC News )

According to John Skerritt, head of the TGA, the process of listing cannabis products under the PBS is underway but may take some time.

"The situation we're working towards is for clinical trials to be done and companies to put submissions to us," Professor Skerritt said.

"But those trials take a couple of years, and then they have to get the results and submit them, as they do for any other medicine."

A Senate inquiry is now looking into problems with access and regulation of the industry as a whole.

'It's set up so we fail'

Emma Broughan believes the cost of prescription medicinal cannabis makes it inaccessible for patients. ( ABC News )

Melbourne mother Emma Broughan relies on cannabis to relieve chronic pain caused by a car accident in 2015.

"It changed my life in so many different ways, not just the physical. Obviously it hurts. It hurts a lot every day," she said.

Like Mr Arcuri, Ms Broughan was prescribed cannabis oil by her doctor but was simply unable to afford the prescription.

"It would have ended up costing me a third of my income basically, my pension, to go on this medication," she said.

Ms Broughan believes she is left with no other option than to purchases cannabis products from the black market, a practice which leaves her feeling judged.

While prescriptions for medicinal cannabis are available, Ms Broughan believes the high price means the product remains inaccessible for many Australians.

"It's set up so we'd fail. Here it is, but we can't have it. There is no way I could afford that product," she said.

Mr Arcuri hopes the Senate inquiry will prompt desperately needed change for patients.

"What I hope is that it shifts a bit more of the conversation about the issue," he said.

"It is something that could potentially help millions of more Australians that are not even aware of it at this point."

Despite the experiences of people like Mr Arcuri, there is currently limited scientific evidence that medicinal cannabis is effective against chronic pain.