Documents released under freedom of information laws detail how tensions between festival promoters, pill testers, police and government meant the landmark trial at Groovin the Moo in Canberra almost didn't occur.

An earlier trial planned for the Spilt Milk festival was canned weeks out from the event over a dispute about authorisations.

In February, the STA-SAFE consortium gave formal notification to the government to run the service at the Groovin the Moo music festival at the University of Canberra on April 29.

A working group set up to consider the first pill testing trial had its first meeting in eight months on February 19, and heard Cattleyard was frustrated the application had been discussed with the media before it had been consulted.

The promoter said it would have prefered the government considered alternative harm minimisation strategies and wanted assurances from police they wouldn't arrest patrons who used the service.

Cattleyard also complained about being contacted directly by members of the consortium, even after hours, and said it was more comfortable dealing directly with the government.

The working group said while ACT Policing could indicate support for the service, it could not tell individual officers not to do their job.

It could also not give the promoter an "iron-clad indemnity guarantee" from the government as it would make the government more directly involved.

It had already been decided the previous June that "officious looking government officers might actually be off-putting to potential users" and a hands-off approach from government was preferable.

However, Cattleyard was "wary of the process unless the government takes over full responsibility".

Police were also concerned the promoter was trying to dictate its activity, after Cattleyard demanded patrons who used the service to check drugs for personal use receive "immunity from prosecution".

The promoter also wanted to stop police from using intelligence they had gained at the event later on.

These tensions were left unresolved, and six weeks out from the event, the working group planned to tell the ACT Attorney-General and Police Minister the event was not going ahead at Groovin the Moo.

It suggested that third parties might want to consider providing the service at a smaller rural event.

This advice was based on the experience of paramedics at the Psyfari festival at Tharwa in February.

The ACT Ambulance Service reported "high resource demand" at the Caloola Farm bush doof, which had five callouts, three transports to hospital, including two sedations, for about 2000 attendees.

It said this was a "significantly higher acuity than recent urban festivals".

"Due to the lack of regulation patrons at these events are potentially at higher risk so pill testing could be a valuable intervention to reduce drug use and resulting harm," meeting minutes from March 13 this year read.

It was noted unofficial pill testing was already taking place at the event with reagent kits, and the event was "lower profile".

At a meeting the following week, Cattleyard also suggested trialling pill testing at a smaller, lower profile event, as was the initial model overseas.

“Cattleyard are supportive of the concept of pill testing but want increased risk sharing before they’ll support it at their festival," meeting notes read.

Days later, the promoter said it felt it was "a risk to GTM reputation" if pill testing was offered but someone who used the service then got prosecuted.

The working group also considered off-site pill testing on the day of Groovin the Moo at another site on the University of Canberra campus.

The Alcohol Tobacco and Other Drug Association ACT had suggested at a meeting in June 2017 an off-site testing centre should be available part-time in the weeks leading up to a music festival.

However it was decided it was outside the original scope of  the pill testing trial agreed to by cabinet in 2017, and it would require starting from scratch, which was not possible in the time frame.

Ultimately, the trial got the last-minute go-ahead.

Two deadly substances were picked up, including one linked to mass overdoses overseas, and 42 per cent of participants indicating they would change their behaviour after seeing what was in their drugs.

No one who used the service was arrested or presented to on-site paramedics.