Exactly what went wrong on Dreamworld's Thunder River Rapids ride.

Almost 24 hours on from the Dreamworld accident that claimed the lives of four adults, further information about what happened in those final moments has emerged.

Tragedy struck the Gold Coast theme park on Tuesday afternoon when Kate Goodchild, her brother Luke Dorsett, his partner Roozi Araghi and New Zealand woman Cindy Low were all killed on the Thunder River Rapids ride.

Incredibly, Goodchild and Low's children were thrown from the ride and avoided any serious physical injury.

Trouble began when nearing the end of the ride, the group's six-seater raft made its way onto an automated conveyor belt designed to carry patrons towards the disembark point.

Somehow, an empty raft in front of the group's became jammed and the two collided within moments.

Upon impact, the raft carrying the group of six flipped and Goodchild's 12-year-old daughter and Low's 10-year-old son were thrown from the ride.

Speaking to news.com.au on Wednesday, Queensland’s assistant police commissioner Brian Codd admitted it was “almost a miracle” that the two children survived.

“In terms of how they escaped, maybe through the providence of God or somebody,” he said, adding, "If we’re going to be thankful for anything, I’m thankful for that.”

Following the collision, two of the four adults were killed by the conveyor belt and another two died while trapped under the raft.

Within hours, an investigation into the accident was launched and Dreamworld announced the park will be closed until further notice, with a statement reading; “Dreamworld is currently closed until further notice due to an incident at the park.

"We are deeply shocked and saddened by the incident; our heart and thoughts go out to the families involved and their loved ones.”

The deaths come just two weeks after a concerned mother wrote to Dreamworld warning them “Someone will get seriously injured or killed one day.”