Maintenance planner Grant Naumann conceded issues such as pinch points had been overlooked with the 30-year-old ride before a malfunction in October 2016 led to the deaths of four visitors.

Mr Naumann was one of three employees to testify as the inquest into the deaths of Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi resumed on Monday at the Southport Coroners Court.

Counsel assisting Ken Fleming QC asked Mr Naumann if there had been a "total failure by everybody" to identify risks with the ride.

"In hindsight, yes," Mr Naumann replied after a long pause.

The fatal incident occurred after a water pump failed, dropping water levels and leaving a raft stranded on a conveyor belt.

Operators failed to shut down the conveyor belt before the raft containing the four victims collided with it, forcing both rafts to flip and the visitors to suffer fatal injuries in the ride's machinery.

Mr Naumann had earlier said he believed some maintenance operations may have been deferred for budgetary reasons.

But he said he had never been told explicitly he could not attend to safety issues due to monetary factors.

The inquest also heard an emergency stop button on the main control panel of the ride was never checked by a maintenance supervisor.

"That button was not a part of our pre-operational checks," maintenance supervisor Stephen Murphy said.

Mr Murphy also revealed senior management had altered a policy to allow a ride to break down three times in 24 hours before it was shut down.

"It was passed down from the management meeting that we would do it that way," Mr Murphy said, adding he didn't know when the order to extend it from two break downs in one day had been made, or why.

Dreamworld replaced the chain and several wooden planks on the conveyor during annual maintenance in April 2016, the inquest heard.

The inquest was also shown a work order from October 26, 2016 - the day after the tragedy - scheduling annual preventative maintenance on the Thunder River Rapids ride for 2017.

Mr Naumann said he did not know who had raised the work order.

Junior engineer Gen Cruz was appointed to undertake a safety and maintenance audit of every ride at the park but had not reviewed the Thunder River Rapids ride at the time of the tragedy.

He said the audit had been necessary due to a "lack of documentation and outdated maintenance program".

Mr Cruz said because the Thunder River Rapids ride had been built in-house by the previous owners in the 1980s, it lacked things such as service bulletins for maintenance procedures.

The inquest continues on Tuesday.

Australian Associated Press