Parents have delayed taking their epileptic children to hospital over fears they will be taken off black market medicinal cannabis being used to control seizures.
Epilepsy Action Australia clinical governance manager Lisa Todd said patients were unable to be given illegally-obtained medicinal cannabis - or "unregulated product" - in hospital.
"Despite it being the only product that would actually control their child's seizures when they're not on any other medication and everything else has been exhausted," she said.
"That's a really big issue because we have had families who have actually delayed admission and surgeries because of that fact, or they've been threatened with calling the police while they're in the hospital."
The comments were made to a Queensland parliamentary committee, which is analysing One Nation MP Steve Dickson's medicinal cannabis affordability bill.
The bill asks the health minister to "take steps to ensure whole plant medicinal cannabis is affordable".
It asks the minister to negotiate with the Commonwealth and calls for state or federal governments to subsidise the cost of lawful treatment with whole plant medicinal cannabis imported from overseas.
Epilepsy Action Australia chief executive officer Carol Ireland said some families were getting a supply of medicinal cannabis from compassionate sellers either free or at a low price.
"It's not an option for most of them to pay $100-plus a day [to buy it legitimately]," she said.
People have previously complained of the cost and difficulty accessing medicinal cannabis since it was legalised.
Australian Medical Association Queensland vice president Dr Bill Boyd said there had not been enough studies done on the effects and risks of medicinal cannabis in Australia for it to be subsidised by government or listed on the Pharmaceutical Benefits Scheme at this time.
"Insufficient studies have been done into the subject, thus insufficient level one evidence ... exists to justify such faith being put into these agents that they may be sanctioned by, and paid for by, government," he said.
"We would say that because the science hasn't been done that we'd feel that that would be inappropriate to single out this particular material [medicinal cannabis] for government subsidy where a whole range of other punitive agents might not be."
Health Minister Cameron Dick has previously pushed for medicinal cannabis to be listed on the PBS.
Dr Boyd also pointed out there was widespread use of various products, such as apple cider vinegar, pear juice and turmeric, with claims of their therapeutic benefits.
Dr Boyd said to tell patients to "give it a go and see if it helps you" before more scientific studies were done was not a good way to practice medicine.
But Ms Ireland said some families could not wait for access to medicinal cannabis, and said it was only a small number of the total group who experienced epilepsy.
"The children that have absolutely devastating seizures, so the children that are having multiple seizures a day that are undergoing brain damage as a result of that," she said.
"Those families can't wait for five years or three years or even two years.
"That's why they're using black market product now."
Health Consumers Queensland chief executive officer Melissa Fox said approval processes to the TGA to access medicinal cannabis were becoming faster.
Ms Fox said she hoped federal changes to allow warehousing and bulk importation would guarantee faster supply and a reduction in costs.