Australia Dreamworld: Siblings and couple among dead at theme park

A sister and brother and the brother's partner have been named as three of the four people killed in an Australian theme park accident.

Kate Goodchild and Luke Dorsett, 32 and 35, died on the Thunder River Rapids ride at Dreamworld on Queensland's Gold Coast on Tuesday, their mother said.

Mr Dorsett's partner Roozbeh Araghi was also killed, the ABC reports, along with a woman from New Zealand.

Two children survived in what officials said was "almost a miracle".

The park, one of Australia's biggest, has been closed "indefinitely" and an investigation is under way.

Visitors have been laying floral tributes to the victims at the gates.

(L-R) Kate Goodchild and Luke Dorsett were siblings, while Roozbeh Araghi was Mr Dorsett's partner. Cindy Low was not known to the three.

"Our immediate concern now is to support the families of the victims and to provide appropriate counselling to our visitors and staff," the park said in a statement.

"We are working closely with authorities to understand exactly what occurred."

Four adults, a 10-year-old boy and a 12-year-old girl were on the raft when it flipped after a collision with another raft, Queensland assistant police commissioner Brian Codd told reporters.

The children, who local media say were related to the victims, were thrown free and survived the incident, which Mr Codd described as "almost a miracle".

Two of the adults were thrown from the raft, while two were trapped in the machinery.

Kim Dorsett, the mother of Kate Goodchild and Luke Dorsett, told the Courier-Mail newspaper: "I have three children and have lost two of them today - my whole family has been wiped out."

The fourth victim has been identified by media as Cindy Low, a 42-year-old New-Zealand-born Sydney resident.

The victims' stories

• Kate Goodchild was travelling on the ride with her brother, Luke Dorsett; and his 38-year-old partner, Roozbeh Araghi.

• Cindy 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.

More than 30 investigators are involved in the huge police operation

The theme park, 50km (30 miles) south of Brisbane, is owned by Ardent Leisure Group which saw its shares plunge after the incident.

Australian Prime Minister Malcolm Turnbull said he was "very saddened to learn of the tragic accident".

Worst amusement park accidents

• Eight teenagers 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

• Five children were killed when the Battersea Park Big Dipper malfunctioned in the UK in 1972. Rope hauling cars to the top of launch slope broke and a safety mechanism failed, causing cars to roll into the boarding area

• Three died at the Galaxyland Amusement Park in Alberta, Canada, in 1986. The last car of a four-car train on the Mindbender triple loop ride came away from the track, throwing off passengers before crashing into a concrete pillar

• One person died in a rollercoaster accident at Expoland in Osaka, Japan, in 2007; another was killed at the Darien Lake theme park in New York State, US, in 2011

• Sixteen people - including two teenage girls who needed leg amputations - were injured at UK's Alton Towers park in 2015. Engineers failed to notice a stationary car on the 14-loop Smiler ride and overrode the stop mechanism, sending the next car into it