The NSW government has again rejected the possibility of pill testing being introduced at music festivals, following the death of a man on the weekend.

Callum Brosnan, 19, died on Sunday and three others were taken to hospital after suspected drug overdoses at the Knockout Games of Destiny dance party at Sydney Olympic Park on Saturday night.

"It is a human tragedy," NSW Premier Gladys Berejiklian told the Nine Network on Monday.

The death of Mr Brosnan comes after two people died after overdosing at Sydney music festival Defqon.1 earlier this year.

The drug law reform campaign Take Control wants pill testing at festivals but the premier rejected this, saying the government won't endorse anything that normalises illegal drug taking.

"If we thought it would save a single life, of course, we would go down that path," she said.

"Unfortunately what pill testing doesn't do is really take into account people's different physical attributes. What is safe for one person isn't safe for another."

Two women, aged 19 and 25, and a man remain in critical but stable conditions after being taken to Westmead Hospital on Saturday night.

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.

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