A customs officer displays Captagon pills, part of the 789 kilogrammes (1739 pounds) of confiscated drugs, before its incineration in Sofia, 12, 2007. Reuters/Nikolay Doychinov

As many as 25 people were transported to hospitals after consuming drugs at a Melbourne dance party. Many of those sick after overdosing on drugs were in critical condition.

The incident occurred at the Electric Parade Music Festival at the Sidney Myer Music Bowl on Saturday. It is believed the party-goers consumed synthetic drug GHB.

Twenty-one people were taken to the Alfred, Royal Melbourne and St Vincent’s hospitals. Seven others, who collapsed in nearby parks and streets after leaving the event, were treated at the scene.

According to Ambulance Victoria State Health Commander Paul Holman, the event was "awash with drugs." One man was charged and taken into custody for possession of ecstasy, cocaine, MDMA, LSD, ketamine and hash.

"The majority of those treated by paramedics had overdosed on GHB," Holman said. "It's the highest number of overdoses we have seen at a music event for some time." He added it was the most number of overdoses witnessed at a music festival in a long time. "This is particularly disappointing on a night when Melbourne's out enjoying itself," he said.

Consumption of the drug can cause slowing of the heart and seizures. As a result, those overdosing on it could fall unconscious .

According to one attendee, “majority” of the people at the event were on drugs. “You could see a lot more of GHB. You can tell, the way they sway, the way they look, they're not really conscious,” he said, speaking with 9News.

In light of the massive overdosing on drugs witnessed at the event, people have called for mandatory drug testing. However, no plans to introduce such testing have been made yet.

"This was a tragedy of the proportions that we have not seen when it comes to drug overdoses at these kind of events," Mental Health Minister Martin Foley said. “What we need to do is ramp up our harm reduction efforts, the $192 million that we spend on all sorts of programs around peer support work. Getting the right messages about safe behaviour are clearly not working and we will consider how we have to do more."

Similar sentiment was shared by Victoria Police Chief Commissioner Graham Ashton, who said such testing was “impractical.” He added that gathering results from the testing would require days.

"You could have some quick testing that someone says some drug's OK when it's actually not, caused by the rushed drug testing," he said. "So to do that, at those sort of events, to do it safely and quickly is not really a practical option."