Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi were all killed when the Thunder River Rapids malfunctioned in October 2016.

The four ride passengers were killed instantly from compressive and crushing injuries while Ms Goodchild's 12-year-old daughter and Ms Low's 10-year-old son both survived.

Police said it was a near miracle the two children escaped with their lives after being on the raft that flipped at the end of its ride due to a malfunctioning mechanism.

Dreamworld suffered steep falls in visitor numbers and parent company Ardent Leisure also felt a major drop in revenue following the fatal accident.

After initially announcing it would reopen three days after the tragedy, the theme park shut down for 45 days and is yet to fully recover.

It also led to Ardent chief executive Deborah Thomas standing down in April 2017 before Dreamworld reported a $62.6 million loss for the financial year.

The terms of the inquest say it will examine the circumstances that led up to and caused the fatal incident, as well as the construction, maintenance, safety measures, staffing, history and modifications of the ride.

Coroner James McDougall will also look at the sufficiency of the training provided to staff in operating the ride and how to prevent a similar incident from occurring.

Several hearings have already been held before Monday's inquest, all attended by lawyers for the four victims, Dreamworld chief executive Craig Davidson, Ardent Leisure and the Office of Industrial Relations.

It is set to be held in two parts, beginning with a two week hearing at Southport Courthouse where more than 50 witnesses are expected to be called.

Among the first witnesses to give evidence are set to be police, including principal investigator Detective Sergeant Nicola Brown and Detective Inspector Mark Thompson.

Ardent Leisure says it will cooperate throughout the inquest.

"This will be a difficult time for many, our hearts and thoughts remain with the families and all those affected by the tragedy," the company said in a statement.

A second overflow court room, with a live feed of proceedings, will be set up due to the large amount of media, family and lawyers.

Late last year, Kim Dorsett, mother of Ms Goodchild and Mr Dorsett, said the 12 months on from the incident had been filled with tears and disbelief, where even "getting out of bed can be a major achievement".

Australian Associated Press