Roundup: 4 killed in accident at Australia's largest theme park on Cold Coast

Australian authorities have set up a crime scene at Australia's largest theme park after four people tragically died from an amusement ride malfunction.

The Thunder River Rapids ride at Dreamworld on Queensland's Gold Coast suffered a malfunction on Tuesday afternoon, causing two people ejected, while the other two were trapped inside the ride itself.

"Two males and two females... were assessed by Queensland Ambulance personnel and had all sustained injuries that were incompatible with living," Queensland Ambulance acting senior operations supervisor Gavin Fuller told reporters.

A coronial investigation into the exact cause of deaths is underway, with workplace health and safety authorities and forensic investigators at the scene.

Local media reported the ride had been closed earlier in the day due to safety issues, however QLD Police inspector and southeast region duty officer Tod Reid told reporters he was not aware of any problems "but that will be part of the investigation."

The park was evacuated shortly before 16:00 local time (AEST) as confirmation of their deaths came through.

Australian Prime Minister Malcolm Turnbull said Tuesday was a "very sad day," with his "thoughts and prayers" with the family members of those who lost their lives in the "very sad, tragic event."

The park's owners Arden Leisure Group said the park would remain closed on Wednesday "as a mark of respect for the victims and their families."

"Dreamworld is working as quickly as possible to establish the facts around the incident and is working closely with the police, emergency services and authorities to do this," the company said in a statement.

"Dreamworld's focus and priority is with the families of those involved in this tragedy and will be providing an update to the public as soon as information becomes available."

Adren's shares slumped 7.84 percent to 2.35 Australian dollars (1.80 U.S. dollars) on Tuesday.

While Australia's tourism marketer Tourism Australia has been enticing Chinese tourists to visit the country, Tuesday's accident will only heighten safety concerns for those who visit.

The River Rapids Ride, opened in 1986, is Australia's only rapids ride after Dreamworld's Rocky Hollow Log Ride was shut down in April after a man had fallen out of the ride and nearly drowned.

The tragic event is the eighth major amusement park accident Australia has experienced since high-wire stuntman Adrian Labans fell to his death during a high-wire act at the Royal Hobart Show in October 1968.

Tourism Australia did not immediately respond to Xinhua's request for comment. Endit