His search for alternative medicines to treat his daughter Katelyn's catastrophic epilepsy led him to cannabis oil.

Within hours of administering the oil for the first time, the toddler's symptoms improved dramatically.

"It made an immediate difference," Mr Lambert said.

"She slept through the night and just started talking like she never had before the next morning."

Hospitalised eight times in the previous four months, Katelyn has been home since starting on cannabis oil 10 weeks ago.

Mr Lambert, who will appear on a panel at the Inaugural Australian Medical Cannabis Symposium today, is one of an army of Australian parents risking criminal prosecution to ensure their children receive the most effective medical care.

He said watching his daughter suffer almost constant seizures was "absolutely heartbreaking".

"They were just horrific; she would turn blue and you would wonder whether she would ever pull out of them," Mr Lambert said.

"It was like she was being tasered for two hours straight.

"Just imagine if it was your child."

The cannabis oil the father of five gives his daughter has little or no THC, the chemical which gets users high.

Since using the oil, the Lamberts have been able to take Katelyn off many of the benzodiazepines and barbiturates she was being forced to use.

"This oil is a miracle, it gives me hope for the future," Mr Lambert said.

Mr Lambert's cannabis conversion has seen him send letters to politicians across the nation, urging their support.

But the spectre of prosecution still looms large in his mind.

"I'm hiding oil and giving some to different family members so I don't get caught with it all at once," he said.

"If police came knocking on my door I could get 25 years' jail."