A move by the Greens to make medicinal cannabis use a defence against a drug-driving conviction has been voted down in the New South Wales state parliament.

The amendment to the Road Transport Legislation Amendment Bill, moved by Greens Member of the Legislative Council David Shoebridge, stated: “It is a defence to a prosecution… if the defendant proves to the court’s satisfaction that… the presence in the defendant’s oral fluid, blood or urine of delta‑9‑tetrahydrocannabinol was caused by the consumption of a substance for medicinal purposes.”

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Greens MLC David Shoebridge

Shoebridge said the matter had caused “significant concern” in the community and that although anyone driving while impaired by a drug should lose their licence under section 112 of the Road Transport Act, section 111 — which makes it an offence to drive with the “mere presence” of ecstasy, cannabis or amphetamines — was too broadly defined.

He added: “The concern for the Greens has always been in relation to the offence for driving with a slight trace element of cannabis in somebody’s system because the sensitivity of the test… has been repeatedly used to find drivers in breach of section 111 and to remove their licences. This often sees them economically and socially isolated as a result. Of course, this has the greatest impact on regional New South Wales.”

He cited evidence from the Bureau of Crime Statistics and Research which showed most prosecutions and driver licence losses under section 111 occur in the North Coast, Lismore and Northern Rivers regions, as well as south‑west Sydney.

“There are many hundreds, indeed thousands, of cases where a driver has lost their licence not because they were impaired or because they were a danger but because they had the smallest, tiniest trace element of cannabis in their system.”

Shoebridge said the issue has become more pressing as laws around medicinal cannabis use have relaxed and consumer access has improved, but those taking medicinal cannabis to deal with chronic pain still have no defence under section 111.

He added: “These are people who often have a desperate need for a licence to get medical attention, to maintain their connections with family or… the community, and they automatically lose their licence — there is absolutely no defence.”