Mr Barr revealed on Monday his government had approved Pill Testing Australia's second drug-checking trial for the April festival, saying the service offered last year had convinced him to support it and invite politicians from the Opposition and other jurisdictions along to observe.

He said he "didn’t start in the yes camp for pill testing but I am there now" and was "comfortable that pursuing these trials in the way that we are is the right public policy".

"I’m not putting up pill testing as a panacea that will solve every problem. It won’t. But we believe it does make a difference, it does make an important difference at a particular moment in time, so that's why we're supporting the trials," Mr Barr said.

When asked if a drug death during the trial would prevent future ones from taking place, Mr Barr said: "No, I don't think so".

"If you take the counterview and look at the public policy approach in Australia for the last several decades it’s hardly worked and it’s hardly prevented deaths either," Mr Barr said.

"I think in the end it’s a rounded effort to mitigate risk, it doesn’t eliminate risk, no one is claiming that it does but it is an important and timely intervention when someone is making a considerable decision as to whether they would take a pill or not."

NSW Labor's health spokesman is understood to have accepted an invitation, but the Canberra Liberals legal affairs spokesman Jeremy Hanson also said he will attend the trial, despite his opposition to the service.

"I’m very happy to go and have a look at the way it's conducted," Mr Hanson said. "We want to do everything we can to keep people safe."

However he still feared that testing the drugs would send a message to wider festivalgoers that they were safe, and wanted the government to consider other measures like enhanced medical support, following the example set by NSW.

"People are still going to take illicit substances, I understand that, but we’ve just go to do the best we can to keep the safe and all the measures we take are effective and don’t have unintended consequences an my fears pill testing will have that," Mr Hanson said.

Mr Barr said they  were "stepping up" their efforts with regards to the presence of ACT Ambulance and ACT Health at the festival, although it was "fairly standard" for them to be involved in an event of that size.

Mr Barr also said he would not rule out paying for pill testing services in the future, but would not make a decision until he has seen the Australian National University's independent evaluation on of the trial.

Unlike last year, the consortium will not evaluate their own trial, with a team from ANU to be inside the tent recording data and reviewing the service. 

Greens drug law reform spokesman Shane Rattenbury said a business case for ongoing trials was probably the next step in the process.

"At this stage it’s great that this is a volunteer effort. I think if you were going to make it a long term sustained project, to run it every weekend at an offsite facility you would need to look at a different funding model," Mr Rattenbury said.

“My experience of visiting this in the Netherlands is that it has become a standard government service that it is funded as part of the health budget and like all of these things there are savings attached to that as well, less hospital admissions, less acute cases, less ambulance use.

"All of those things can provide real savings so it would be valuable to think about how we would put together a business case that shows he cost savings as well as the saving of lives."