The 24-year-old Shepparton man was taken to the medical tent at the festival by the banks of the Murray River about 12.45am on Sunday.

Medical staff were told the man had taken various substances including GHB (gamma hydroxybutyrate), MDMA and cocaine.

Shortly afterwards the man suffered a cardiac arrest and was treated by medical staff.

At 2.02am, he was pronounced dead.

Police are investigating the matter and a report will be produced for the coroner.

Organisers released a statement "begging" people to think about their actions.

"We have implemented every single harm minimisation strategy that is legally available to us, run in-depth education campaigns on the dangers of drug use, and worked closely with all stakeholders to ensure we are in the best possible position to prevent and manage an incident like this," a spokesman said.

"However, we cannot control the choices of individual patrons.

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

The spokesman said organisers were "completely devastated by the news".

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

A large number of festival goers could be seen at the Tocumwal site on Sunday lining up for drug and alcohol testing.

Multiple people have been caught drug driving from the event.

NSW Police Superintendent Jason Weinstein said it was a heartbreaking incident for the man's family, and said drug takers were playing Russian roulette.

"The message I think is very clear from NSW Police," he said.

"Most items are prohibited for a reason, they're illegal for a reason.

"They all have dangerous effects and they can in their own right actually kill people."

Superintendent Weinstein said there was limited information about how the man consumed the drugs, but said "one pill can kill".

"Some information that was given by friends of the deceased was that he took a number of different drugs, a cocktail of drugs," he said.

"The quantities are not known.

"They obviously are matters for the coroner."

Superintendent Weinstein said police supported harm minimisation steps, including drug education at festivals, but not pill testing.

"We don't want to see one person die," he said.