Deadly substances linked to several mass overdoses around the world were detected at a pill-testing trial at this year's Groovin The Moo festival in Canberra.
A new report into the trial also calls for a pilot fixed site for pill testing in the ACT.
The report from Pill Testing Australia into the country's second pill-testing trial, held in April, found seven cases of the lethal substance N-ethyl pentylone. The substance has been linked to multiple overdoses overseas at music festivals.
All seven participants with the substance discarded the pills when they found out what was in them.
The report said 170 substances had been tested for 234 participants during the festival, double the number in the previous year.
MDMA was the predominant substance identified during testing, followed by cocaine, ketamine and methamphetamine.
Of the 170 people who brought substances in for testing, 147 said they expected the sample to contain MDMA.
However, of those 147 who expected MDMA samples, the drug was relatively pure in only 98 cases (67 per cent).
More than 50 of the participants in the pill-testing trial were under 18. The oldest participant was 51.
The report said the majority of those who participated also took part in an intervention with harm-reduction workers after their substances were tested.
More than 200 interventions took place following the testing; 160 of them disclosed they had used drugs previously.
"An integral part of the pill-testing service is that it provides an opportunity for service users to speak about their drug use with tailored consideration for their risk profile," the report said.
The first two pill-testing trials were labelled a success by Pill Testing Australia. The organisation said government funding was needed to allow the service to continue at future music festivals in the ACT.
Among recommendations outlined in the report were calls for a pilot fixed site for pill testing in the ACT.
"No matter how strong our desire for people not to use drugs or our efforts at education and prevention, people will continue to use drugs," the report said.
"It is imperative to understand that first and foremost, all of us want those we care for and who may be using drugs, not to be harmed."
The ACT was the first jurisdiction in Australia to conduct a trial of pill testing.
Following the success of the trial in Canberra, Pill Testing Australia extended the offer to conducting a free trial at music festivals in other states and territories.
After multiple overdose deaths at music festivals in NSW, Premier Gladys Berejiklian said pill testing would not be carried out, despite calls for the services from medical experts.
An independent report into the pill-testing trial at this year's Groovin The Moo, conducted by the Australian National University, is expected to be published later this year.