A man has died from a suspected drug overdose at a southern New South Wales music festival.

Key points: A man died at the Strawberry Fields music festival after reportedly taking drugs including MDMA and cocaine

A man died at the Strawberry Fields music festival after reportedly taking drugs including MDMA and cocaine Elsewhere, police arrested four people at a Sydney event over allegedly supplying drugs

Elsewhere, police arrested four people at a Sydney event over allegedly supplying drugs Police also issued 13 people with on-the-spot fines rather than court appearance notices for drug possession at the Sydney event

Police said the 24-year-old was taken to the medical tent early this morning at the Strawberry Fields festival in the Riverina.

Medical staff were told he had taken multiple substances including GHB, MDMA and cocaine.

The man suffered a cardiac arrest and was pronounced dead at 2:02am.

Officers from the Murray River Police District are investigating.

A lengthy statement from the festival organisers said the team worked year round to ensure the 9,500 festivalgoers were hosted in the safest possible environment.

"We are completely devastated by this news," the statement said.

"We would like to send our sincere condolences to his family and friends during this distressing and terribly sad time."

Revellers at the Strawberry Fields festival on Saturday. ( Instagram: Stavroz_official )

However, organisers urged festivalgoers to take responsibility for their actions.

"We have implemented every single harm minimisation strategy that is legally available to us … however, we cannot control the choices of individual patrons," the statement said.

"We are begging people to stop and think about the ramifications of their choices on their family and friends and to stay safe."

Police make 137 drug detections at Sydney festival

Meanwhile, four people have been charged with supplying drugs at the Festival X music event yesterday at Sydney Showground.

Police said they reached 137 drug detections over the 10-hour festival which was attended by more than 44,000 revellers.

And as part of a NSW Government trial, 13 people were issued with on-the-spot fines for drug infringement, a move supported by police for dealing with recreational users at festivals.

The fines, known as criminal infringement notices which carry penalties of up to $400, are a discretionary power and aimed at avoiding court attendances.

Neither of the festivals are on the NSW Government's "high-risk" list which carries tighter licensing restrictions.

This latest death follows huge scrutiny of NSW music festivals this year on the back of a coronial inquest after six people died at events over two summers.

Deputy NSW coroner Harriet Grahame has recommended the use of pill-testing, the decriminalisation of personal drug use and banning sniffer dogs at festivals.

The Berejiklian Government has steadfastly voiced its opposition to pill testing, which the Premier said sent the "wrong message".