A Sydney woman has died, another is in a coma and 120 people have been treated for drug-related illnesses at the Stereosonic Music Festival.
Frustrated police revealed the dire toll a day after the event that attracted 48,000 revellers, saying the drug culture at music festivals needs to change.
A 25-year-old woman from Oyster Bay in Sydney's south consumed a mixture of ecstasy and other drugs at the festival at Sydney Olympic Park before falling ill on Saturday afternoon.
She was taken to Concord Hospital and pronounced dead at 9:30pm.
"The message does not seem to get through to some people," said South West Assistant Commissioner Frank Mennilli.
A second woman, 22, was found unconscious and taken to Westmead Hospital where she was placed into an induced coma.
She is now in a stable condition.
A further nine people were taken to hospital for treatment and later discharged.
Mr Mennilli said the police's attempts to warn people about the effects of drugs were falling on deaf ears.
Almost 70 people were arrested at Stereosonic on Saturday, with seven people charged with drug supply.
Mr Mennilli said more police would have made little difference in combating drug use.
"I can honestly tell you that if I had more police dogs and more police, it'd just result in more people being arrested," he said.
The party drugs available at music festivals were especially dangerous given their 'home-made' production.
"They're cooked up in backyards. You just don't know what impurities are put in these drugs," he said.
"You put these things in your body, you don't know how your body is going to react."
The death of the 25-year-old comes two months after the death of 26-year-old Albury man Nigel Pauljevic at the DEFQON1 music festival in Penrith, and just over a year since the death of 19-year-old Georgina Bartter.
Ms Bartter died after taking ecstasy supplied to her by her best friend at the Harbourlife Festival last November.