Road Traffic Act 1974

If in any proceeding for an offence against section 64AC, 64B or 64C it is proved that a certain drug was present in the accused’s body at any time within 4 hours, or 12 hours if the sample was taken under section 66(8B), after the time of the driving or attempted driving of a motor vehicle that gave rise to the alleged offence, the presence of that drug in the accused’s body at the time of that driving or attempted driving is taken to be proved in the absence of proof to the contrary.

If a person takes a prescribed illicit drug mistakenly believing it to be another drug, that mistake is not a defence in any proceeding for an offence against section 64AC, 64B or 64C if that other drug is also a drug within the meaning of paragraph (a) or (b) of the definition of drug in section 65.