A teenager has died and 16 others have been hospitalised following suspected drug overdoses at a dance music festival in Sydney's west on Saturday night.

Nineteen-year-old Callum Brosnan, from Baulkham Hills, was found at Sydney Olympic Park train station, then taken to Concord Hospital where he died around 4.30am.

The alleged drug offences have reignited debate about pill-testing. Credit:Harder Styles United

Two women, aged 19 and 25, and a man were taken to Westmead Hospital in a critical condition, but on Sunday afternoon had woken up from induced comas and were in a stable condition.

Police say 13 other people were hospitalised and 130 sought medical treatment at the event.