The area, known for its long, winding roads has hosted a number of serious crashes over the years.
Police say they have been made aware of the incident and are now conducting an investigation.
They urge anyone with dashcam footage or further information to make make themselves known to detectives.
The incident, which was reported at 5.45pm on Sunday, occurred while the male was riding the 199 bus.
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It comes following a string of recent incidents involving busses across the state.
“The safety and security of our customers is paramount to Transport for NSW. We do not condone reckless and dangerous behaviour,” a Transport for NSW spokesperson said.
“NSW Police are investigating this incident and Keolis Downer, the operator of the bus, is assisting police with their investigation.”