MARIJUANA use is highest among those aged in their 30s, while teenagers are taking notice of advertising campaigns warning of the drug's effects.
The statistics have been used by the Federal Government's peak drug policy adviser to highlight the work needed to be done in the "war on drugs".
"The interesting thing is that there are fewer young people smoking marijuana now," former federal minister John Herron said yesterday.
"It's an older cohort. In fact, the main cohort is the 30 to 39-year-olds, the dominant ones, whom I think escaped that sort of era of being concerned about it."
Dr Herron said one of the problems was the availability of marijuana and the number of people who used it in association with other illicit substances.