Low was visiting the theme park with her two children and her husband, local media said.

She decided to separate from her daughter and husband and ride in another raft with her son and four strangers.

The Thunder River Rapids ride opened in 1986. Dreamworld says it allows visitors to "travel down a foamy water track" in circular rafts.

The Australian Workers Union said it had raised "grave concerns" about safety on rides at the park more than a year ago, though not about the river rapids ride specifically.

Forensic police are reviewing CCTV footage and investigating the scene. They will submit a report to the state coroner alongside workplace safety authorities and the coroner will decide if any charges should be filed.

Worst amusement park accidents

Eight teenagers were killed in a 1984fire at the Six Flags Great Adventure amusement park in New Jersey, US. Arsonists are believed to have started the blaze

were killed in a 1984 fire at the Six Flags Great Adventure amusement park in New Jersey, US. Arsonists are believed to have started the blaze Six people died in a failed simulated rocket launch in Shenzhen, China, in 2010. One of the cars on the centrifuge ride became loose, lost power and the ride fell to the ground in flames with 44 people inside

died in a failed simulated rocket launch in Shenzhen, China, in 2010. One of the cars on the centrifuge ride became loose, lost power and the ride fell to the ground in flames with 44 people inside Five children were killed when the Battersea