Chief Minister Andrew Barr once ate a pot brownie, and Labor backbencher Michael Pettersson - who's behind the bill to legalise cannabis coming up for debate next month - also confirmed he'd experimented with drugs before.

Police Minister Mick Gentleman said he hadn't tried modern drugs, "but in the 70s I certainly tried cannabis".

"I think that was a time when we all tried different things, that was something in our youth. It's good to learn from that, but of course drug taking is dangerous and I encourage most people not to take drugs," Mr Gentleman said.

City Services Minister Chris Steel said he was "part of the 10.3 per cent of Australians who have used MDMA" at a handful of electronic music festivals when he was younger.

"The music festivals that I’ve been to no longer exist, but widespread drug use at music festivals continues, and that’s why we need to look at new ways to reduce harm like pill testing," Mr Steel said.

He said he'd also tried marijuana, but it wasn't for him.

Greens crossbencher Caroline Le Couteur said she'd both smoked and grown cannabis when she was younger, and had also tried acid.

"As I’ve said before, I’m an ageing hippie from Nimbin," Ms Le Couteur said.

Labor backbencher Bec Cody said the only drug she'd ever done was alcohol and "maybe one puff on a joint about ten years ago".

"I had three coffees last year which was a lot for me," Ms Cody said. "I think drug prohibition and the war on drugs is a failure [though]. It seems to me that the criminalisation of some drugs causes more harm than the drugs themselves.”

Labor's Suzanne Orr also said she'd tried cannabis when she was younger, but was thankful that since then harm-minimisation programs like pill testing "have helped young people make better decisions about their health and wellbeing".

The Liberals' police spokeswoman Giulia Jones said she'd never tried drugs, although she "smoked a rolled up newspaper in high school".

"I had a pretty quiet upbringing I’d say," Mrs Jones said.

The Liberals' legal affairs spokesman Jeremy Hanson said he'd never done drugs either, as he'd joined the army when he was 18 and spent the next 22 years in the military.

Alistair Coe, James Milligan and Mark Parton also said they'd never done drugs, although Mr Parton said he was severely addicted to caffeine.

However Health Minister Meegan Fitzharris said her colleagues' personal experiences with illicit drugs did not matter, and had no bearing on the pill testing debate.

"We make our harm-minimisation policies based on evidence, not the personal experiences of ministers," Ms Fitzharris said.

"The ACT government supports trialling pill testing because the evidence and expert advice tells us that it can help young people make better and more informed decisions at music festivals."

Liberal senator Zed Seselja said he'd never tried drugs, but was worried about the message that admissions from politicians could send to young people.

"I wouldn't want to see a message going out from any of our leaders to suggest that, yes, because they tried drugs when they were young that somehow that makes drug use safe," Senator Seselja said.

Mr Hanson also played down the importance of past experience with drugs to today's debate.

"[Mr Rattenbury] said he took one tablet in his 20s. I don't think that is of consequence to the current debate about drug policy to be honest. He’s done something he regrets when he was younger, I’m more focused on what we can do to make young people safe at festivals and elsewhere," Mr Hanson said.

"I do understand drugs are prevalent in society, young people will try them, I don't have my head buried in the sand here. Regardless whether Mr Rattenbury took a drug in his 20s and I didn’t, the debate is here and now about what we do to keep young people safe and my view is pill testing will do more harm than good."

However Ms Le Couteur said it was "very helpful in terms of the debate to know where politicians’ life experience is".

"Politicians, we're meant to be representative of the community and it’s fair enough that the community has an idea of what our relevant experiences are," Ms Le Couteur said.

Mr Rattenbury said his drug-taking experience had helped to shape his views on the issue of pill testing, combined with evidence from the Canberra trial and overseas.

"I look at my own example and think about how naive I was and I wish I’d had better information or better knowledge of what the reality was," Mr Rattenbury said.

"That's something I’m very conscious about now as we think about the policy of it, is that I think a lot of young people are in those situations where perhaps the opportunity arises and they grab that opportunity and they shouldn’t die as a result of it."

However Mrs Jones said while honesty was important, so was enforcing the law.

"I think that the people of the ACT deserve ministers who are absolutely committed to illegal drugs being completely stamped out, not encouraged among our young people," Mrs Jones said.

• with Cassandra Morgan