Experts believe the Dreamworld accident could cost millions.

The emotional toll of yesterday’s Dreamworld disaster will be felt by many for years to come.

However, as investigations continue into what caused the ride malfunction behind Queensland’s worst theme park tragedy, someone will inevitably need to be made accountable — and it could cost millions of dollars.

Police have said “no stone will be left unturned” as they attempt to get to the bottom of the incident, which left four adults dead.

“We owe it to the deceased and their families, we owe it to the community of Queensland, to get to the bottom of what caused this,” Assistant Commissioner Brian Codd told reporters this morning.

“If and where there is criminal aspects, including negligence, which warrants being pursued we will do that.”

Kate Goodchild and partners Luke Dorsett and Roozbeh Argahi, all from Canberra, were killed when two rafts on the the 30-year-old Thunder River Rapids hit one another at the end of the ride, tipping one backwards.

Another unidentified 42-year-old woman also died.

The three victims of yesterday's Dreamworld tragedy. Source: Facebook

The ride is expected to remain a crime scene for two or three days, but Dreamworld will remained closed indefinitely with serious questions being raised about ongoing maintenance practices at the popular holiday destination.

Authorities will use CCTV footage to try and pinpoint exactly what went wrong.

A legal expert has speculated the corporation that owns the park could face financial penalties of up to $3 million while any individual found to be negligent could face up to five years in prison.

"A tragedy like this isn’t an act of God, it’s not a freak accident," Alison Barrett of Maurice Blackburn Lawyers told The Courier Mail. 

"They tend to occur ­because of a disregard of someone’s safety."

Earlier this year a man nearly drowned on neighbouring ride, the Rocky Hollow Log Ride, which forced a shutdown and an investigation in April.

Samson Sherrin, 19, suffered hip and foot fractures, neck and head injuries, and acute respiratory failure after falling out of the popular log ride that operates on the same conveyor belt system as the Thunder River Rapids.

He also suffered pneumonia as a result of the time spent in the water and cuts on his body.

An official from the Australian Workers Union (AWU) confirmed the group had ongoing concerns about the maintenance and operation some of the amusement park's equipment.

"We did hold some very grave concerns about safety of equipment and the operation of equipment," he told the ABC.

"I don't want to inflame the situation.

"However we do think that in the interests of workers at that facility, but also to the patrons of that facility, people who visit it for an enjoyable experience, that it is important there is a full inquiry."