According to a company official who refused to be named, the victim was working as a ballast control operator on the unit.
Labuan OCPD Supt. Adzhar Othman visited the scene to get first-hand information and ensure no stone was left unturned in the investigation.
"So far, no foul play is suspected, but we have to look at all angles.
Some bruises on the head and body of the victim, identified as Ross Flett, were consistent with a fall from more than 100 feet, the height of the platform" Adzhar told Daily Express. The oil rig was situated at the Bay of Brunei, some nine nautical miles from here.
Adzhar said the police took a very serious view of the accident in view of the importance of the emerging oil and gas industry.
He disclosed that the marine police were notified of the death on the same day the body was found at about 11am.
Flett was found missing during a roll call at 7am on that day. An alarm was sounded and a search and rescue operation was mounted immediately which was also joined by fishermen near the oil rig.
At about 9.10am, Flett was pronounced without vital signs.
His body was laid on a pontoon when the police arrived and spent three hours scouring for evidence and interviewing his colleagues.
It is believed that Flett was alone when he fell.
No one saw him on the night as the shift already ended at 7pm.
The body was taken to Hospital Labuan for a post-mortem.
Queen Elizabeth Hospital's forensic specialists were informed and flown here before they were taken to the platform.
Adzhar said police would wait for a full autopsy report before taking the next course of action.