David Randall, from DRA Safety Specialists, said he was employed by Dreamworld in 2013 to perform a safety management systems audit - not to check the rides for potentially fatal flaws.

In October 2016, four people died on the Thunder River Rapids ride, which was considered the lowest-risk attraction at the theme park, the inquest was told on Thursday.

Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi died after a water pump malfunctioned, resulting in two rafts colliding and flipping.

The inquest was told there had been more an 20 attempts to recreate the accident that claimed four lives, but the circumstances could not be repeated.

Mr Randall said the fact it could not be repeated meant the incident was an accident.

"If they had asked me to audit the rides, I may have picked up some of these issues. That was not my brief," he said.

Had they asked, Mr Randall would have gone through the records and inspected rides to identify any potential hazards - a process he has carried out for 15 years at Village Roadshow theme parks.

"That is not what they wanted."

In his initial full safety audit, Dreamworld scored just 41.7 per cent by comparison, and compliant business would require a score of 75 per cent.

When questioned if the low score meant the park should have closed to improve standards, Mr Randall said it was not a practical option and there was a five-year plan to improve safety.

Coroner James McDougall questioned whether it would have been appropriate to have someone inspect each ride to see whether they had any fundamental faults that could endanger lives before auditing the safety systems.

"That is not what they requested me to do. They wanted my safety hat, not my engineering hat," Mr Randall said.

During the systems audit, Mr Randall said there had been pushback from staff when he tried to improve operational procedures.

"It was hard to overcome. Many of the people had been there for 25 years with their ways. It was a cultural thing that we had to move forward," he said.

"The management was good - very, very good - but there was resistance to change in the workforce because this is not what they had done for the last 20 years."

Mr Randall said staff were required to perform a checklist for ride safety, but many did not follow the criteria.

"They would cover off the requirements off the checklist, but they all had their own system. I was still finding people doing things their own way."

Australian Associated Press