A man is in intensive care in hospital after an apparent drug overdose at the Melbourne Stereosonic music festival on Saturday.

Ambulance Victoria said the man, aged in his late teens, was one of six suspected overdoses treated by paramedics at the Flemington showgrounds in Melbourne.

He was taken to the Western Hospital in a critical condition, but is now considered to be in a serious, but stable condition.

Another reveller aged in his 20s was taken to the Royal Melbourne Hospital in a serious condition, after suffering head injuries in a fall, but he has since been discharged.

The suspected overdose comes after a 19-year-old man died and two people in their 20s were taken to hospital in a critical condition after suspected drug overdoses at Adelaide's Stereosonic event.

Police said a 20-year-old man was taken to the Royal Adelaide Hospital after suffering from a medical episode at the event in Bonython Park.

"It appears as though he also consumed an illicit substance and he remains in a critical but stable condition in hospital," a police statement said.

A 21-year-old woman is also in a critical but stable condition in hospital "after ingesting an illicit substance", police said.

Almost 70 others were charged with drug offences at the Sydney Stereosonic festival.

Dozens of drug arrests at Melbourne Stereosonic

Victoria Police arrested 70 people and seized drugs including ecstasy, MDMA, amphetamines, cocaine and cannabis at the Melbourne festival on Saturday.

Six people were issued with cannabis cautions and two others are expected to be charged on summons with drug offences and two were charged and bailed.

They also said two festival goers were expected to be charged on summons with assault, while two others were issued with penalty notices for being drunk.

Meanwhile, South Australian police have released images of the red or orange pills stamped with dollar symbols found in the man's possession in Adelaide.

Police seized 34 pills and six people were evicted from the Adelaide event.

Superintendent John De Candia said 34 people were refused entry after they were found to be carrying drugs.

Twenty-three people were issued with drug diversions to attend counselling.