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.

A government facility for growing medical marijuana in Israel. Credit:Getty Images

"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."