Police will allege a 19-year-old man sold pills known as "purple speakers"  to a third party who then gave the drugs to the 19-year-old Longueville woman.

His arrest came just hours before another Sydney teenager died from a suspected overdose at a rave event held at Sydney Olympic Park in the early hours of Sunday.

Police are investigating whether the man who died at the weekend had been competing with friends to see who could swallow the most ecstasy pills.

Another man, 20, who attended the same State of Trance dance party remained in a serious but stable condition after he  suffered a suspected overdose.

A few hours before the Homebush rave had even started, police investigating Ms Bartter's death raided a home in Robert Street at Willoughby about 5.30pm on Saturday.

It is alleged officers found the man in possession of illegal drugs and he was later charged with  three counts of supplying a prohibited drug and one count of possession.

He was granted conditional bail to appear at Downing Centre Local Court on Wednesday, March 25.

Ms Bartter, a former Wenona student, died after she had a suspected adverse reaction to drugs she took last year.

More than 700 people  packed into the pews of St Mary's, North Sydney, for her funeral last year.

A common theme shared by those who knew her was her vivacious personality and the way in which she made people laugh.

The Longueville teenager spent much of 2014 working with her father so she could afford to go travelling with friends.

"She has been and always will be his beautiful girl," her mother Mrs Bartter said.

After the most recent dance party, at least five people were taken to hospital with suspected overdoses.

Assistant Commissioner Frank Mennilli said he believed a number of people were involved in an "idiotic" game at the event.

"The information I have at this stage is that, basically, they were taking [pills] as a game," Mr Mennilli said.

"Look, shocking isn't the word; idiotic is the word. These people were gambling with their life; it's absolute stupidity, really there are no words for it.

"A 19 year-old has lost his life – what a tragedy, what a waste."

One reveller said he remembered seeing the teenager who died, just after he lost consciousness.

"I saw him on the ground and we got told by the security to move on," he said.

Mr Menilli said he was shocked to learn of a 22-year-old who accidently swallowed a bag of pills he was trying to hide in his mouth from police.

"He had them in a plastic bag in his mouth and he tried to secrete them and accidentally swallowed them," he said.

In a panic, the man told police what had happened and he was rushed to hospital but released later on Sunday.

Police arrested 40 people for supplying and possessing drugs, including one man who was allegedly caught with 130 ecstasy pills, and another with 98.

"They were there preying on people who were there and silly enough to buy them."

More than 16,000 people attended A State of Trance, which ran from 10pm to 6am in three exhibition halls at the Sydney Showground, with a headline set from Dutch trance DJ Armin van Buuren.

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