A man remains in a critical condition while two more are still hospitalised following a suspected mass drug overdose in Melbourne on Friday night. 

As Fairfax reports, at least nine people were taken to hospital following the I Am Hardstyle dance event at Festival Hall. 

An 18-year-old punter was still in a critical condition on Sunday morning, while a 17-year-old man was also in hospital in a stable condition. 

While Victoria police continue to investigate the drugs that were taken, it has been confirmed they involved para-Methoxyamphetamine; a stimulant often sold or mistaken for ecstasy.

"They are certainly lucky they didn't die on the spot," Ambulance Victoria state health commander Paul Holman said.

"They had St John Ambulance there providing first aid, they had a doctor there who was providing intervention.

"If they hadn't been there, certainly some of these young people might not even have got to the hospital."

Meanwhile, over 150 people have been charged with drug-related offences at Sydney's Electric Gardens Festival on Saturday and HTID Dance Party yesterday. 

Police confirmed in a statement that the charges from Electric Gardens, headlined by Fatboy Slim, included two people being charged with resisting an officer and one person for assault. 

A 20-year-old man was found with 50 capsules believed to be MDMA and a 25-year-old man was caught with 31 capsules believed to be MDMA and cannabis.