A man has died and two people are in hospital after taking an "unknown substance" at the Lost Paradise Music Festival on the NSW Central Coast.
The 22-year-old Queensland man was taken to Gosford Hospital about 8pm on Saturday but died a short time later, police said.
A man and a woman remain in hospital in a stable condition after ingesting the substance and becoming ill at the festival at Glenworth Valley, near Gosford.

The 2017 Lost Paradise festival. Source: Facebook
In a statement, a spokeswoman for the festival said "this is a very distressing incident and our sincerest thoughts and condolences are with the family and friends of the deceased".
"Lost Paradise is a strictly drug-free event that is about celebrating life, love and nature in a fun, safe and welcoming environment ... We work closely with local police to try to ensure festival-goers respect our drug-free policy and NSW Ambulance to provide extensive medical support across the festival site," the spokeswoman said.
'A tragic event'
On Sunday, NSW Police Force Acting Superintendent Rod Peet said he was "frustrated" people were bringing illicit substances to a drug-free event.
"The determination by some people ... and the secretion [methods] have been quite significant. Unfortunately, some drugs have got through," he said.
He said "methods of secretion" had become "more sophisticated" at the event this year, including Vegemite jars with false compartments, aerosol containers and "on one instance ... someone inserted drugs into the stuffing of a barbecued chicken".

Acting superintendent Rod Peet talks to reporters. Source: SBS News
Mr Peet added that those making the drugs were clearly using "risky products".
"It's a tragic event ... The best message I can say is don't use illicit drugs."
He said police will continue to work throughout the festival.
"They're still going be tenacious, they're still going to be vigilant, if they've got to search more chickens to find drugs, they will be doing that."

The festival will continue until January 1. Source: Facebook
About 11,000 people attended the festival which started on Friday and continues until January 1.
More than 180 people and 97 vehicles have been searched during a police drug dog operation at the festival and three people have been charged with drug supply offences, police said.
A 21-year-old man from Drummoyne was charged after allegedly being found with 105 MDMA pill and a 23-year-old man from Elanora Heights was charged after allegedly being caught with 80 MDMA pills and 65 bags of cocaine.
Both men are due in Gosford Local Court on January 18.
A 23-year-old man from Glendale, near Newcastle, was allegedly found with 26 MDMA pills, and was issued with a field court attendance notice for supplying a prohibited drug.
He is due to appear in the same court on February 5.
With AAP