A person can carry three times as much MDMA into a music festival and still be eligible for a $400 on-the-spot fine, in lieu of facing a court, if the drugs are carried in a form other than a capsule, in what legal experts have called a "double standard".

The rule, which falls under a trial policy introduced almost one month ago, comes after the death of two young people at a music festival last year and a recommendation from an expert government-commissioned panel. Three more people have died after taking drugs at festivals since.

Carrying MDMA in pills or powder can change a person's eligibility for an on-the-spot fine that avoids a court appearance.

Legal experts and advocates say the rule promotes a "double standard" because it determines a person's eligibility based on the way they carry drugs, for example in a capsule or in powder form.

"It partially decriminalises [drug-taking] in one form, while maintaining it as criminal in another," said criminal lawyer John Sutton, managing partner of Armstrong Legal.