A man has died and eight others have been taken to hospital after attending dance music festival in western Sydney on Saturday night, police say.

The 26-year-old man from Albury was found unconscious in a tent about 11:30pm at the Defqon. 1 festival in Penrith.

The man's friends had tried to revive him before paramedics arrived to find the man unconscious.

He was treated at the scene before being taken to Nepean hospital where he later died.

Police said a coronial investigation is underway to determine if the 26-year-old might have taken illegal drugs.

Detective Inspector Grant Healey warned drug-takers that it was friends and family who were left to deal with the aftermath of drug-related incidents.

"[Friends and family] live with the scars for the rest of their life," he said.

"Quite often they are the ones doing first aid, watching their friends pass away. So if you're taking those drugs, just remember they don't just affect you."

Officers have been targeting the use of illegal drugs at the music festival, where in 2013 a man died after taking three pills.

Police said many people had not heeded their continued warnings over drug-related incidents.

"People are dying from taking drugs," Detective Inspector Healey said.

"People have got to realise if you put something in your mouth, you don't know what it is, it can kill you."

Defqon. 1, which attracts thousands of people each year, said on its website it had zero-tolerance drug policy.

Police said the festival and dance party organisers were not to blame.

Defqon. 1 said on its website its "highest priority during is to create a memorable and above all safe Defqon. 1 experience". ( Facebook: Defqon. 1 Australia )

"Festivals and dance parties aren't the problem, it's people making poor adult decisions that are the problem," Detective Inspector Healey said.

"If you read... what the festival has put out, they tell people... they have got a no drug policy, so it's adults making really poor adult decisions."

The Defqon.1 website states its "highest priority during is to create a memorable and above all safe Defqon. 1 experience for everyone who comes to party with us".

"We want to make you aware that the use of illicit substances carries a range of health risks including the possibility of death, and is strictly forbidden at this event," the website states.

Police ran an operation targeting drug use and arrested 60 people at this year's event, 46 which were for drug offences.

Four people were arrested for drug supply, while two people were caught with 46 pills, believed to be MDMA.

Nine festival-goers were taken to Nepean Hospital by paramedics.

A spokesperson from Q-Dance Australia said the organiser of the festival continued to give its full support to the authorities in their investigation.

"At present, our thoughts and prayers are with his family and friends," the spokesperson said.

"Everyone on our team is deeply shocked and affected by this tragic event.

"Until the NSW Police investigation is completed and respecting the privacy of the family, we cannot make any further statements."