Kiwi one of four dead in accident at Dreamworld

A Kiwi woman was one of four people killed in a horror accident on a Gold Coast theme park ride.

The Herald understands the woman and one of her children were on the Thunder River Rapids ride at Dreamworld when the accident happened about 2.20pm local time (5.20pm NZT).

Originally from Auckland, the woman had been living in Australia with her Kiwi husband and their two children, who were on holiday on the Gold Coast at the time.

Their son, who was also on the ride is said to be recovering in hospital, his father by his bedside.

LISTEN: Australian correspondent Donna Demaio speaks to Rachel Smalley about the Dreamworld tragedy

Shocked relatives in New Zealand were preparing to rush to the Gold Coast to support the family.

Police said two men, aged 38 and 35, and two women aged 42 and 32 died.

Meanwhile, reports emerged last night that Dreamworld visitors said there had been problems on the ride earlier in the day.

The Thunder River Rapids Ride at Dreamworld. Photo / Supplied

A witness told Nine News they were waiting for half an hour while engineers attended to the ride.

"They drained all the water out and then had to refill it back up, and then we were allowed to go. But yeah, we were stuck there for about 30 minutes at least," the witness said.

Queensland police spokesman Tod Reid said he wasn't aware of any earlier issues with the ride, and couldn't say if the four people who died were related.

A woman whose sister and niece were on the fatal river rapids ride said: "They are so traumatised, there is a woman hanging by her foot, crushed from the ride."

The Thunder River Rapids ride is a raft ride using a conveyor belt. Australia's only river rapids ride, it opened in December, 1986.

Riders board one of several six-person circular rafts.

The raft is dispatched and the riders enter a cave, before exiting into the main rapids section of the ride. This runs alongside a large water catchment that powers both the Thunder River Rapids ride and the Rocky Hollow Log ride.

Riders speed at up to 45km/h through turbulent rapids.

The riders were understood to be trapped in the conveyor belt.

A witness told Brisbane's Courier Mail the ride flipped at the very end of its circuit.

In this image made from video, rescue personnel stand by the Thunder River Rapids ride at Dreamworld on the Gold Coast. Photo / Channel 9 via AP

A man told the Courier Mail a girl was pulled from the ride just before it flipped. He thought four people were on the ride.

Witness Leah Capes said she was waiting near the ride entrance when people came running from the rapids ride line.

"The kids and people in there were screaming.

"It all happened so quickly. There were heaps of people crying."

Prime Minister Malcolm Turnbull offered his condolences. "I'm very saddened to learn of the tragic accident at Dreamworld," he said last night.

Dreamworld chief executive Craig Davison said the park was closed and Dreamworld was "working to establish facts around the incident".

Queensland Ambulance Service spokesman Gavin Fuller said a malfunction caused two people to be thrown from their raft and another two were caught inside it.

They were assessed by ambulance staff but had suffered fatal injuries.

He said ambulance staff were "deeply affected" by the accident.

He said he couldn't be more specific on the nature of the injuries or how the four passengers died.

Reid said the forensic crash unit and workplace health and safety were at the scene of the accident.

He said police were working with Dreamworld to determine what happened.

Gold Coast Mayor Tom Tate issued a statement reflecting the community's shock at the news. "This is a very sad day for our city," he said.

"Our thoughts are with the families of those affected - and the emergency staff in attendance."

A House of Travel spokesman said the Gold Coast was "probably New Zealand's most popular short-haul family holiday destination". Nearly 190,000 Kiwis travelled to the Gold Coast in the year to last March.

The same conveyor belt system used to operate the deadly Thunder River Rapids ride at Dreamworld was to blame for a near death on a similar ride at the park in April this year.

The previous accident on the log ride nearly caused a man in his 30s to drown after the conveyor belt slipped and trapped him.

Workplace Queensland and independent inspectors had to give the ride the all-clear before it was able to reopen again.