At about 1.00am on Sunday, two armed men forced their way into a unit on Roscoe Street and confronted two men staying at the apartment.

The occupants were assaulted by the intruders, whose faces were concealed and were armed with a firearm and a blunt object.

The armed men fled and the police were alerted.

One of the occupants who was assaulted by the pair has not been seen since the incident. A 26-year-old man was also injured during the assault.

Investigators are appealing for public assistance in an attempt to locate the missing man, who sustained significant injuries during the attack.

"Concerns are held for the man's welfare," police said.

Details concerning the man's identity are scant. He is believed to go by the names Eddy or Michael, and his surname is possibly Scott.

The man is described as Caucasian appearance, believed to be in his late 40s, about 175cm tall, with short dark hair and a greying beard.

The man, who speaks with an English accent, was last seen wearing a dark jacket and camouflage-coloured cargo shorts.

The man may work as a painter and frequents pubs and clubs in the Bondi area.

Anyone with information on the man's identity or whereabouts is urged to contact local police or Crime Stoppers on 1200 333 000.