A faulty water pump and a raft that became stranded were the likely cause of four deaths that occurred when a ride malfunctioned at Dreamworld on the Gold Coast in 2016, a court has heard.

A pre-inquest hearing into the deaths of Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi heard the group were killed "almost instantly" when they were thrown from the ride.

Counsel assisting Ken Fleming told the hearing the victims and two children were in the fifth of the nine rafts on the Thunder River Rapids ride, described as a "moderate" ride to simulate white water rafting.

Queensland Emergency service personnel at the Thunder River Rapids ride. ( AAP: Dan Peled )

Mr Fleming told the Brisbane Magistrates Court they had completed the course without incident, however the sixth raft became stranded, and the victims' raft flipped when a collision occurred.

One of the ride's pumps had stopped working 15 seconds earlier, causing the water level to drop, Mr Fleming said.

"Each died almost instantly as a result of compressive or crushing injuries as a result of coming into contact with the mechanism of the conveyor," Mr Fleming said.

The two children in the raft managed to escape.

Mr Fleming proposed splitting a formal inquest into the deaths into two sections — the first to examine exactly what happened and the response to the fatal incident, and the second to look at whether law changes were needed to prevent similar tragedies.

The construction, maintenance and modifications to the ride will also be within the inquest scope, along with Dreamworld's risk-management processes, training and staffing.

The first half of the inquest will likely be heard in June and July, with proposed dates for the second portion slated for October, November and December.

The list of witnesses to testify has not been confirmed.

The dates are yet to be formalised.

Lawyers for Ardent Leisure, Dreamworld's parent company, said they would cooperate with the inquest.

Mr Fleming said the inquest would not result in blame being laid on any parties, but acknowledged the Director of Public Prosecutions and Workplace Health and Safety Queensland could take their own legal action.

Outside court, Mr Fleming said he hoped the victims' families would get some closure from the inquest.

Floral tributes outside Dreamworld for the four victims of the ride malfunction in 2016. ( ABC News: Ashleigh Stevenson - file photo )

He said there would be a lot of evidence to come out and that he had "a terabyte" of documents relating to the case.

"There is an enormous amount of work to be done to get on top of the facts — a lot of people's interest [are] at stake here," Mr Fleming said.

Cindy Low's family said they hope the inquest provides answers and "prevents any other family going through such enormous heartbreak".

"Our lives were turned upside down that day by the loss of Cindy, we have spent each week and month comforting each other and learning how to live without her."

A second pre-inquest hearing will be held at the Southport Magistrate Court on May 25.