Traffic Act 1987

(1) It is a defence to a prosecution for an offence against section 28(1) if:

(a) analysis of a blood sample or saliva sample taken under this Part:

(i) gives no indication of any drug mentioned in section 19A(a); but

(ii) does indicate the presence of a drug (or drugs) mentioned in section 19A(b); and

(b) the defendant satisfies the court as to the matters mentioned in subsection (2).

(a) the defendant was, at the time of the alleged offence, under treatment by a medical practitioner and had taken the drug as part of that treatment; and

(b) the defendant had taken the drug in accordance with the directions of the medical practitioner.