Teen Georgina had travelled the world, but death came so close to home

Only a few months ago Georgina Bartter was treading a well-travelled path across Europe.

Like most parents, her mother and father may have felt some anxiety about the dangers their teenage daughter could face on the other side of the world.

But the event which ended her life happened only kilometres from their home in Sydney's Longueville.

Ms Bartter, 19, who the family describe as a beautiful and vibrant young woman, died in St Vincent's Hospital on Saturday night after a suspected drug overdose.

She was found convulsing on the ground of the Harbourlife dance party at Mrs Macquarie's Chair on the harbour.

Irishman Owen Mullins said he noticed her looking unwell and told her friend she needed help.

"She agreed and asked for a paramedic so I ran and got one," he posted online.

"I thought she would be saved ... this is terrible terrible news, she was so young."

Ms Bartter, who finished year 12 at Sydney's Wenona girls school just last year, was rushed to hospital but suffered multiple organ failure and died.

Her friends told police she took one and a half pills before she collapsed.

However, her family believe she may have had an allergic reaction.

The death has sent shock waves through her circle of friends and family, including relatives in regional NSW.

Ms Bartter's mother Kirsty comes from the Riverina, where her family runs Wagga Motors.

St Vincent's emergency department director Gordian Fulde was on duty when Ms Bartter was brought in.

He says party pills are made with designs to make them look attractive to young people.

"You could have two pills from the same dealer and one doesn't work that much and the other one will blow your brains out."

A post-mortem will be carried out to determine the exact cause of Ms Bartter's death.