A Dreamworld maintenance planner says there was a “total failure by everybody” leading up to the deaths of four people on the Thunder River Rapids ride.

An inquiry into the deaths of Cindy Low, Kate Goodchild, Luke Dorsett and Roozi Araghi at Dreamworld in 2016 has resumed this week.

All four died on the ride after their raft collided with an empty vessel and flipped backwards.

The inquest this week heard that some ride repairs were delayed for budgetary reasons, despite Dreamworld's own safety guidelines warning of the potential for rafts to tip.

Counsel assisting the coroner, Ken Fleming QC, grilled Dreamworld maintenance planner Grant Naumann, who concede the Thunder River Rapids ride was “completely unsafe”.

Ken Fleming QC: "The day that this accident occurred, this ride proved to be completely unsafe, didn't it?"

Grant Naumann: "Yes."

K.F: "Whose job was it to determine the safety of the ride?"

G.N: "Everybody's."

K.F: "Are you then saying that there has been a total failure by everybody to identify the safety issues in respect of this ride?"

G.N: "In hindsight yes."

Mr Naumann told the inquiry that modifications had been made to the Thunder River Rapids ride conveyer belt before the fatal incident.

“We installed some framework at the base of the conveyor, so leading up to the conveyor,” he said.

“That framework was put in there in the event that a water level dropped the raft couldn't tip over, that sort of thing.”

Additionally, maintenance team leader Stephen Murphy revealed that management had recently instructed staff to shut down rides if they broke down three times in one day.  The previous breakdown policy dictated a ride be shut down after two issues.

The Thunder River Rapids ride broke down twice on the day of the fatal raft collision.