Four people are dead after the Thunder River Rapids Ride at Dreamworld on the Gold Coast malfunctioned, trapping at least one person in the conveyor belt.
The group -- two men aged 35 and 38 and two women aged 32 and 42 -- were killed after the ride flipped, with two people being ejected from the ride and the other two becoming trapped underneath at around 2pm on Tuesday afternoon.
In a press conference on Tuesday evening, Queensland Police Inspector Tod Reid said that forensic teams have examined the victims' bodies "in situ" and police were in the process of identifying them and contacting familes.
It has not yet been confirmed whether the victims were related.
"I can't give a time frame as to how long we will be here for," he said.
"However, it is a complex retrieval involving heavy equipment and that will take several hours."
Inspector Reid also noted that the moment when the ride flipped has been captured on CCTV footage.
"That will be reviewed as part of the investigation."
"We are deeply shocked and saddened by this and our hearts and our thoughts go to the families involved, and their loved ones," he said.
In a statement published at 8pm, Dreamworld confirmed the four deaths and said they will be offering support to the victims' families and counselling for visitors and staff.
"The entire Dreamworld team is devastated and shocked by this incident," the statement read.
Dreamworld is closed until further notice.
One of the rides malfunctioned, causing two people to be ejected, an Ambulance Queensland spokesman told media.
Another two people became trapped inside the ride. Park staff gave them first aid. The victims were aged between 32 and their early 40s, he said.
An investigation had started by 6pm, with a Workplace Health and Safety Queensland team on site, with the organisation's chief engineer. The team will work with the Queensland Police Service.
"This is an absolute tragedy and our hearts go out to the friends and relatives of those who died today," Office of Industrial Relations Executive Director Julie Nielsen said in a statement.
Queensland Premier Annastacia Palaszczuk said the incident was "absolutely devastating" and authorities "want to leave no stone unturned".
"The police want to get to the bottom of this, because we want to ensure that nothing like this ever happens again," Palaszczuk said on The 7:30 Report.
"My own family went there earlier this year and we actually went on the exact same ride. This is a ride that thousands and thousands of families have been on.
"We do not want anything to jeopardise the Gold Coast as a world-class tourist destination.
"I want to stress to people, please keep coming to the Gold Coast, show your support, because we will get to the bottom of what happened here, and we want to reassure people that Queensland is a safe place to come and visit."
The QLD Premier said she would provide counselling services to paramedics, Dreamworld staff and witnesses traumatised by the incident.
"We need to make sure that everyone gets the counselling that they need. Also, people who have left the theme park and who are also concerned or traumatised, we want to reach out to them," Palaszczuk said on Tuesday night.
Prime Minister Malcolm Turnbull said it is "a very sad day" and he trusts there will be a thorough investigation into the four deaths.
The accident happened on the Thunder River Rapids Ride, which is described on the Dreamworld website as taking visitors "speeding up to 45 km/h through the turbulent rapids".
Dreamworld visitors told Fairfax the ride had "broken down" earlier on Tuesday morning. The minimum age restriction for the ride is two years old.
The operator of Dreamworld, Ardent Leisure, has had its share price drop 8 percent since the incident -- which you can read more about here.
Thunder River Rapids Ride
- Thunder River Rapids is categorised as one of Dreamworld's family rides;
- Dreamworld's description of the ride reports it reaches speeds of up to 45 km/h;
- It is rated as "moderate thrill" and kids as young as two can ride it;
- The circular rafts hold six people. After travelling down the rapids, the ride ends with a conveyer belt which takes the rafts back to the entry station.