Three weeks after two festival-goers died from suspected drug overdoses at Sydney's Defqon.1, ACT Greens leader Shane Rattenbury is pushing to relocate the festival to Canberra.

Key points: The NSW Premier has appointed experts to find out how to keep music festivals safe

The NSW Premier has appointed experts to find out how to keep music festivals safe But she has ruled out supporting pill testing

But she has ruled out supporting pill testing The ACT is the only Australian jurisdiction to have trialled pill testing

The New South Wales Government initially vowed to "do everything we can" to shut down the Penrith hardstyle music festival, after a 23-year-old and 21-year-old died and three others were left in a critical condition during the event.

About 700 people at the event sought medical help.

Mr Rattenbury has written to festival organiser Q-Dance, inviting it to bring future festivals to Canberra where pill testing could be carried out.

It comes after Canberra's Groovin the Moo festival in April became the site for Australia's first official pill-testing trial.

"This is a great event, I think it would be great to bring it to Canberra from a tourism point of view, to have something for our young people to go to," he said.

The Greens leader said he wanted to work with the organisers to make the festival as safe as possible.

"At Defqon, because there was no pill testing, we saw people were obviously taking drugs without any ability to check them," he said.

"I think … a really important part about having it here in the ACT would be offering that service."

Defqon.1 runs in Australia, the Netherlands and Chile and mainly showcases hardstyle dance music.

The Penrith event has been marred by drug overdoses in previous years, including in 2015 when a man was found unconscious and later died in hospital

In 2013, a 23-year-old man died from a suspected overdose while 14 others were hospitalised, and 84 people were arrested for drug possession.

But Mr Rattenbury said the event could be an economic boost for Canberra.

"I see no good reason not to have this festival here, it's a big event, we want to see more things like this happening in Canberra," he said.

"We need to have a spectrum of opportunities for people when it comes to entertainment and something like Defqon can fit into that and it can be a great economic opportunity for this city as well."

NSW Government 'has head in sand': Rattenbury

In response to this year's event, NSW Premier Gladys Berejiklian established an expert panel to advise on how to keep music festivals safe.

However, she ruled out pill testing as an option.

Mr Rattenbury said that response was disappointing.

"The NSW approach of just sticking their head in the sand is no way to run festivals," he said.

"I'd prefer people didn't take pills when they went to festivals but in the real world they do, and that's what we need to prepare though."

Mr Rattenbury's letter pointed to the support for April's pill-testing trial from ACT Police and the ACT chief health officer and noted the identification of highly toxic ingredients and new drugs authorities did not know were circulating the ACT.

"The trial [at Groovin the Moo] was able to realise a nation-leading harm minimisation approach to what is, fundamentally, a public health issue," he said.

"The Greens want to do our best to ensure festival-goers have a good time in the safest ways possible, rather than taking avoidable risks."

Q-Dance is yet to reply to Mr Rattenbury's letter.