The 76-year-old, who cannot be named for legal reasons, was found by police with minor head injuries following reports of a possible shooting in the inner city suburb of Darlinghurst.

Residents called police to report hearing a single gunshot and a man yelling just after 4am on Tuesday.

Police arrived to find the man in Barcom Avenue, not far from his home in Womerah Lane.

Police are investigating whether he was hit with the butt of a rifle.

The man, a former bodybuilder and scientist, was arrested in 2015 and charged with supplying 14 grams of heroin.

He is due to face a District Court trial in July.

The elderly man was a recognised figure around Kings Cross, known for speaking to crowds on a soapbox in the Domain on Sunday afternoons.

The man was taken to St Vincent's Hospital on Tuesday morning but was released about four hours later.

Detective Superintendent Michael Fitzgerald said the man was well known to police in the area and would face court in July over the alleged commercial supply of heroin.

"I can say to the public this was not a random act, it was a targeted attack," he told reporters in Kings Cross.

The man's daughter and another person were home at the time.

"This is a brazen attack on a male person who is well known to police, but that does not take away from the fact that members of the public are entitled to feel protected in their houses," Detective Fitzgerald said.

"This has obviously shaken them up."

Officers have spent much of Tuesday morning scouring the crime scene for evidence of what type of weapon was used.

"A crime scene has been established which is being forensically examined," a statement from NSW Police said.

"Inquiries are continuing into how the man became injured and whether any shots were fired."

Anyone with information should contact Crime Stoppers on 1800 333 000.

with AAP

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