A young, gifted musician may have taken up to nine MDMA capsules before dying at a music festival in NSW, an inquest has heard.

Key points: Callum Brosnan died after the Knockout Games of Destiny event in December 2018

Callum Brosnan died after the Knockout Games of Destiny event in December 2018 Friends say it was normal for Mr Brosnan to take around 10 MDMA pills on a night out

Friends say it was normal for Mr Brosnan to take around 10 MDMA pills on a night out An inquest into a string of deaths at NSW music festivals will examine why young people take drugs

The coroner is investigating a string of drug-related deaths at festivals across the state over the past two summers, which prompted a crackdown from the State Government.

On Monday morning the inquest examined the death of Callum Brosnan, 19, who died after attending the Knockout Games of Destiny event in December 2018.

Counsel assisting the inquiry Peggy Dwyer said Mr Brosnan's friends purchased 30 MDMA pills from a dealer on the day of the festival.

While they could not be sure how many he ingested, they said he took the most out of the group and estimated he may have taken six to nine.

Mr Brosnan became very unwell at Sydney Olympic Park train station where he lost consciousness and his temperature rose to 41.9 degrees Celsius.

Ms Dwyer told the court Mr Brosnan was "very bright and very kind" and was a gifted musician.

She said his use of MDMA began in 2014 and friends reported he would sometimes use up to 10 pills on a night out.

"Because he functioned so well and was doing so well in life and was so clever and creative and was getting on with his life as a responsible young adult, Callum's parents were not aware of his interest in drugs," Ms Dwyer said.

The inquest will examine the deaths of six young people who took varying amounts of MDMA and died under different circumstances, including whether they drank alcohol or not.

Ms Dwyer said over the next few weeks they would examine why young people took illicit drugs.

"In this courtroom, there is no judgement of the young people themselves nor of their friends who may have participated in drug use with them," she said.

Deputy Coroner Harriet Grahame extended her condolences to the many family members who were attending the inquest.

"Your grief must be profound and ongoing," she said.

"These are your children but they could just as easily be the children of my own community or my own family.

"We owe them a proper investigation of the circumstances in which they died."

Following the six drug-related deaths, pressure mounted to change the ban on pill testing but NSW Premier Gladys Bereijklian refused, saying it was a "green light" to take drugs.