Australian authorities are investigating the death of a Malaysian girl who was flung "like a doll" from a spinning ride at the Royal Adelaide Show where showgoers laid flowers for her Saturday.

The girl, 8, who was reportedly visiting Australia with her family, was thrown from the AirMaxx 360 ride on Friday afternoon, South Australian police said in a statement.

She was treated by paramedics and taken to an Adelaide hospital but died a short time later, police said.

Malinda Dunwoodie said she was near the ride when she saw the child "flying through the air".

"She was hanging by her legs off the ride, trying to block herself," Dunwoodie told Adelaide newspaper The Advertiser.

"She went flying through the air about 10 to 15 metres (33 to 49 feet) up in the air and I started sprinting towards her. I was shaking so much, she looked like a doll flying through the air.

"It was so shocking —- it was like a horror movie. I didn't see her land in the crowd but when I made it over to her I couldn't see her eyes moving. Everyone was screaming."

Showgoers on Saturday laid stuffed teddy bear toys and flowers at a makeshift memorial in the showgrounds.

"It's just complete sadness and it's a tragedy that should have been avoided," Katherina Ritson, one of the event's staff who placed flowers, told the Australian Broadcasting Corporation.

A spokesman for the High Commission of Malaysia told AFP they were working with the country's Honorary Consul in South Australia to assist the family.

South Australia's work health and safety agency, SafeWork SA, said the ride -- which was operating for the first time at the show -- would be shut for the rest of the event as they investigate the incident with police.

The ride, about 15 metres long and 18 metres wide, resembles a giant spider and can carry up to 24 people.

The Royal Adelaide Show attracts about half a million visitors every year and is South Australia's largest event. It features amusement rides as well as farming exhibitions with live animals.