A doctor deregistered in 2005 for supplying cannabis oil to his patients has reportedly claimed he will never stop supplying the illegal tonic to his patients in the face of "unjust" laws.

Dr Andrew Katelaris is manufacturing cannabis oil in a "secret laboratory" near Sydney, which he then distributes around Australia, the Herald Sun has reported.

He declared Australia's health ministers were "criminal" for refusing the treatment to adults and children suffering from debilitating and terminal illnesses.

Dr Katelaris has previously been arrested and charged with a number of drug offences, but said he would continue to defy police and called on them to exercise discretion in their persecution of his patients.

He claims to deliver cannabis oil to 12 children around Australia, as well producing cannabis resin for a number of older patients.

“When the law is unjust, resistance is mandatory,’’ he said.

The Victorian government has indicated it will allow pharmaceutical trials of cannabis-based medicine.

NSW Premier Mike Baird and opposition leader John Robertson have both said they would principally support the legalisation of medical cannabis, but they said there would need to be strict controls.