Queensland authorities say the number of people treated for drug overdoses at the Stereosonic music festival in Brisbane was staggering.

Event organisers went all out to ensure the festival's Brisbane leg was safer after a 19-year-old man died in Adelaide and a 25-year-old woman died in Sydney from an overdose.

Extra ambulance officers and security staff were hired to supervise patrons, but ambulance officials say it did not stop people taking drugs.

Paramedics took 20 people to Brisbane emergency departments overnight for treatment of drug overdoses.

"We cannot express our concerns highly enough regarding the dangers of drug use," Stereosonic said in a Facebook post ahead of the festival.

"We have tragically lost two lives to drugs during our festival and whilst every effort has been made to protect you and keep you safe with our teams of professional medical and security staff, ...you as individuals need to make smart choices and understand the risks you are taking.

"As media reports have indicated there are various highly dangerous substances on the market and there is no way of knowing what is in them. Do not gamble with your life today."

The family of Stefan Woodward, 19, who died at the Adelaide Stereosonic from a suspected drug overdose, is calling for safer measures to "keep kids safe" at music festivals. ( Supplied: Facebook )

Sylvia Choi, 25, from Oyster Bay, died after overdosing at the festival's Sydney leg.

A man has been charged with drug supply after it was alleged he provided the MDMA that killed Ms Choi.

One week after Ms Choi's death, 19-year-old Stefan Woodward also died from a suspected overdose at the Adelaide Stereosonic.

His family has since come forward to urge other young people to "not be afraid" to ask for help and to watch out for their mates.

"I want organisers of events like these to make sure there is enough first aid on offer to make sure that no-one gets turned away, and no-one feels they need to wait," the family said.

"I want friends to look after each other and make sure it's never considered weak to ask for help. I want authorities to make sure kids are kept safe with free water.

"And I want young boys and girls like Stefan to never be too scared to ask for help."

Mother of overdose victim urges pill testing

Emergency physician Dr David Caldicott was part of a growing number of experts pushing for pill testing at music festivals in light of the drug-related Stereosonic deaths.

He labelled this the "most dangerous season" Australia had ever seen with new drugs appearing on the market.

Sylvia Choi, 25, was one of two people to die from a suspected drug overdose at this year's Stereosonic music festivals. ( Supplied: NSW Police )

Police released images of red and orange pills that were found on Mr Woodward the same died he died — pills which seemed to slip through the police net and into the festival.

Adriana Buccianti, who lost her son to drugs in 2012, has joined Dr Caldicott's calls for pill testing.

Her son Daniel, 34, died after taking acid at the Rainbow Serpent festival in Victoria.

"It's a horror beyond horror that your children go before you in any circumstances," Ms Buccianti told ABC 24 Breakfast.

"What I'd like to see is the drug testing at festivals. I think it will prevent deaths, I really do.

"I sincerely believe if Daniel had somewhere where he could take those substances and he would have been told what was in them, the potency of it, he wouldn't have taken it.

"This is not about condoning drugs, it is about protecting our children, the future of tomorrow."