A pill testing trial at Canberra music festival Groovin the Moo detected seven dangerous substances in more than 100 samples, advocates of pill testing say.

Australia's second pill testing trial has been declared a success by advocates after detecting dangerous substances which were then binned by festival-goers.

The ACT government allowed the pill testing trial at Canberra's Groovin the Moo festival on Sunday following an Australian-first pilot last year.

The trial tested 171 samples from 234 participants with MDMA the most prominent substance identified, according to a joint media release from Pill Testing Australia, Take Control and Harm Reduction Australia.

Seven dangerous substances containing N-Ethylpentylone were detected, with patrons using an amnesty bin to toss the drugs once alerted.

N-Ethylpentylone is often mis-sold as MDMA or ecstasy and has been linked to multiple deaths according to the World Health Organization.

"The pilot was again overwhelmingly successful by any measure but particularly by doing everything possible to keep our kids safe," Pill Testing Australia's Gino Vumbaca said in the media release.

"The simple truth is that it is time to take practical evidence-based steps to make parties and festivals safer."

The trial attracted some interstate interest, with a solicitor involved in an upcoming NSW inquest into music festival deaths among those to observe the set-up on Saturday, along with legal representatives from a NSW inquiry into the drug ice.

The Sydney inquest, which is expected to start in June, will examine the suspected drug-induced deaths of seven young people at NSW music festivals between October 2015 and January 2019.