A coroner says he expects an investigation into the deaths of four people at Dreamworld to take months to complete.
Coroner James McDougall joined detectives at the Gold Coast theme park on Tuesday for a re-enactment of last week's tragedy on the Thunder River Rapids ride.
More News Videos
- Video duration
- 01:29
Dreamworld investigation 'very complicated'
- Video duration
- 01:27
Shootings 'shocking and traumatic'
- Video duration
- 01:02
Three dead in Hervey Bay shooting
- Video duration
- 03:12
Permanent memorial for ride victims
- Video duration
- 01:16
Mum, stepfather charged with Tyrell's murder
- Video duration
- 01:42
Rail debacle costing $1m a fortnight
- Video duration
- 01:07
Kingston pool had 'regulation fencing'
Dreamworld investigation 'very complicated'
Investigators have a "huge amount of work" to find the cause of a Dreamworld ride accident which claimed four lives. 7 News Queensland
Mr McDougall said the re-enactment, which involved the use of weighted crash test dummies in one of the ride's rafts, gave him an insight into the crash.
"It was all very complicated," he said.
"The investigation is going extremely well.
"It will take a long time ... months, I'd say."
Senior police entered the park on Tuesday morning to continuing inspecting the Thunder River Rapids ride that claimed the lives of Canberra man Luke Dorsett, partner Roozi Araghi, sister Kate Goodchild and Sydney woman Cindy Low.
Their bodies were released to their families for burial on Monday following post-mortem examinations.
Investigators closed the air space around the theme park while they undertook their re-enactment.
Dreamworld remains closed, with park bosses saying it will not reopen until at least after the funerals.
About 200 Dreamworld staff returned to work on Monday.
Dreamworld chief executive Craig Davidson has said all staff will be paid while the park remains closed.
In Parliament on Tuesday, Premier Annastacia Palaszczuk said emergency services workers were undergoing counselling after witnessing the "absolutely horrific scene".
"The shock of this tragedy will stay with people for a long time and I want to ensure that everything that can be done will be done to assist those people and those families who witnessed this horrific event," she said.
AAP with Jorge Branco