A coronial inquest into the deaths of four people at Dreamworld has heard there was a "rat's nest" of wiring at the Thunder River Rapids ride control panel that could have led to dangerous malfunctions.

The comment came hours after the inquest was told that even though electricians knew there was something wrong with the ride, they did not look for the cause and just kept resetting water pumps when they broke down.

The inquest also heard a water pump on the ride had broken down five times in the week of the fatal crash.

Kate Goodchild, Luke Dorsett, Roozi Araghi and Cindy Low died on the Thunder River Rapids ride on October 25, 2016, after their vessel collided with another and flipped when a large pump feeding the ride failed and water levels dropped.

Under cross-examination by barrister Matthew Hickey for Ms Low's family, electrician Francoire De Villiers, who reset the ride hours before the tragedy, was shown a photograph of heavy wiring of the control panel.

Mr Hickey asked if the installation was poor.

Mr De Villiers replied: "Yes".

The electrician agreed the wiring could "possibly" lead to dangerous malfunctions of the ride.

Mr De Villiers said he notified his supervisor of the issue each time he performed maintenance and thought there was going to be an upgrade before the fatal malfunction.

The Coroner's Court was also shown a final letter of warning sent by Dreamworld management to Mr De Villiers for a safety breach on a ride one month prior to the fatal incident, in which guests were "significantly jolted".

"In consideration of the seriousness of this matter — you have been issued with a final written warning," the letter stated.

Mr De Villiers told the court he was aware of at least three prior faults when he was called to the ride on the day of the fatal accident and agreed it "rang alarm bells".

"It did. I went to my supervisor, I tested the pump," he said.

Mr De Villiers said he was due to test the motor of the pump the day after the tragedy.

After giving evidence, Mr De Villiers also addressed the victims' family members.

"I just wish to offer my sincerest condolences to all of the family of the victims," he said.

Electricians 'didn't look for cause'

Earlier in the day, a Dreamworld technician told the inquest no electricians tried to identify the cause of pump failures at the water ride in the week of the fatal accident on October 25.

Electrician Jacob Wilson said he helped reset a water pump on October 19 and 22 but neither he nor his colleagues attempted to "diagnose the cause" of the fault.

Roozi Araghi, Luke Dorsett, Kate Goodchild, and Cindy Low lost their lives on the ride. ( Facebook )

The inquest has been told a large water pump feeding the Thunder River Rapids ride failed three times on October 25, the day of the fatalities.

When the ride malfunctioned on the third occasion, water levels dropped and a raft was left stranded on the conveyor belt and a vessel carrying the victims crashed into it.

Mr Wilson was shown the company's breakdown procedure which stated: "If there is a repeat of the fault within the next 24 hours do not attempt to rectify the fault until the Engineering Supervisor has been notified and given authority to rectify the problem".

He said that was not his understanding of the policy.

"I understood it to be if a fault occurred more than twice we were to contact the shift supervisor or a supervisor to discuss what to do next," Mr Wilson said.

Under cross-examination, Mr Wilson agreed a device could have easily been installed to stop the conveyor from moving if the pumps stopped working.

Vision of accident played to closed court

Dreamworld CCTV footage of the fatal accident was played to a closed session of the Coroner's Court hearing.

At least one member of the victims' family chose to remain in the court to view the footage.

The Thunder River Rapids was shut down and never reopened after the fatal accident. ( ABC News: Ashleigh Stevenson )

Counsel assisting the coroner Ken Fleming QC spoke with the media outside the courthouse about the closed session.

"The video wasn't shown to the public because of the sensitivity of it," he said.

"It's awful footage no matter how you look at it and the families of those who died were given the option of being there and it is simply not for public consumption.

"It is a video of the footage from about three or four minutes before the actual incident occurred up to the incident.

"We thought it inappropriate to show the public, but necessary for our purposes to actually see it and to put it in perspective having heard all the evidence we have about it."