The man allegedly threatened the staff member with a firearm, demanding cash, detectives said.
Police said the staff member was unable to access any money, and the man fled the scene.
No one was physically injured during the incident.
“At the time of the incident, it is believed he was wearing some kind of dark material draped around him like a cape and a pair of dark-coloured underpants on his head,” police said.
“He also had on a black t-shirt, light-coloured pants and white runners.”
He was last seen running away from the hotel on CCTV, before tripping on his cape and following on the ground.
Investigators are appealing to the public for information and are hoping to speak to anyone who may have seen the man in the area in the lead-up to or after the alleged robbery.