The same conveyor belt system used by Dreamworld's Thunder River Rapids ride, on which four people were killed on Tuesday afternoon, was to blame for a near-death on another water ride at the park.
The mishap in April in which the conveyor belt for the Log Ride slipped nearly caused a man in his 30s to drown.
Workplace Queensland and independent inspectors were brought in after the incident, and the Log Ride was closed until they were able to give it the all-clear.
The Thunder River Rapids ride remained open after the accident in April. It uses the same conveyor belt system to bring passengers up to station level after they travel through the rapids, the Courier Mail reports.
The ride has been a mainstay of the theme park throughout its 34-year history.
It was advertised a "family-friendly for passengers over 120cm" and travelled at speeds of up to 45km/h.
On Tuesday, two men and two women, aged from 32 to their early 40s, were killed on the ride.
It is believed a conveyor belt malfunction may have forced one of the rafts to flip over.
The park is working with emergency services to figure out what went wrong.