Premier Gladys Berejiklian said on Sunday she was beside herself that young people weren't getting the drug message after a 19-year-old man died and three others remain critically ill following a suspected drug overdose at a Sydney dance party.

The teenager died in Concord Hospital early on Sunday while two women, aged 19 and 25, and a man are in critical but stable conditions at Westmead Hospital after attending the Knockout Games of Destiny dance party at Sydney Olympic Park on Saturday night.

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"Of course we want young people to have fun but don't take an illegal substance, it can kill you," Ms Berejiklian told reporters in Sydney.

"That's why we took the measure to increase penalties for people supplying these illegal substances to a maximum of 20 years."

Asked if it was time to reconsider the government's position on pill testing, Ms Berejiklian said no.

"Unfortunately, we know that pill testing won't work because it'll give people a green light to taking substances, which in the end could still kill them," she said.

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Assistant Commissioner Peter Thurtell said the 19-year-old was found in a distressed state at a railway station nearby the festival as he also pleaded with young people to stay away from drugs.

"(This is) another senseless death of a young person as a result of taking drugs at a dance party," Mr Thurtell told reporters in Sydney on Sunday.

More than 18,000 people attended the dance party.

Police officers at the festival issued 69 banning notices and conducted more than 200 searches, with 62 people found in possession of drugs including one woman who was found with nearly 400 tablets internally concealed.

Police charged several people, including a 25-year-old man who was allegedly found with 145 MDMA capsules in his possession.

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Mr Thurtell said young people aren't getting the message.

"Particularly young men, but young women as well, decide to gamble their lives on the fact that they'll get away with it this time," he said.

"Stay away from it all together because if you keep doing it, eventually it might be you."

Earlier this year, two people died after overdosing at Sydney music festival Defqon.1, prompting the creation of an expert panel to advise the NSW government on drug-related deaths at festivals.

NSW Labor has promised to hold a drug summit in 2019 if the party is elected to government at the March state election.

"There needs to be a broader approach to tackling the scourge of drugs," opposition health spokesman Walt Secord said in a statement on Sunday.

Harder Styles United - the company behind Knockout Games of Destiny - has been contacted for comment.