YEREVAN, OCTOBER 25, ARMENPRESS. Four people have been killed on a ride at a theme park on Australia's east coast, police and park officials say, BBC reports.

Two men and two women died in the Thunder River Rapids ride at Dreamworld on Queensland's Gold Coast, a park spokeswoman said.

The park in Coomera has been closed and an investigation is under way, the spokeswoman added.

Dreamworld bills itself as Australia's biggest theme park with more than 50 rides and attractions.

The Thunder River Rapids ride whisks visitors in circular rafts along a fast-moving artificial river.

Queensland Ambulance spokesman Gavin Fuller said a "malfunction" had caused two people to be thrown from the ride and two had been trapped inside.

The victims have not been identified but reports said they were aged from early 30s to early 40s.

Eyewitness Lisa Capes told Australian broadcaster ABC that she saw people running away from the ride crying.

"I was speaking to one of the guys and he said it was the raft or the boat thing in front of him, the whole thing flipped and everyone was screaming," she said.

The theme park said it was "working as quickly as possible to establish the facts around the incident and is working closely with emergency authorities and police to do this."

In a statement, police said they had been called to the scene following reports that several people had been injured by a conveyor belt.

Craig Davidson, head of Ardent Theme Parks, said they were "deeply shocked and saddened" by the incident.

Police inspector Todd Reid said a crime scene had been established and that the park was working with investigators.

He said he was not aware of any earlier problems with the ride, although that would form part of the investigation.

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

"Theme parks are a place for family fun and happiness, not tragedy," he said.

Queensland Premier Annastacia Palaszczuk said a thorough investigation would be held into the "horrific, horrific scene".

"This has been an absolute tragedy, a tragic accident at Dreamworld where many thousands of people go on a daily basis," she said.