Man, 79, charged with shooting man inside law firm in Sydney's CBD

A 79-year-old man has been charged after allegedly shooting a 77-year-old man in the groin at a law firm on the ninth-floor of a building in Sydney's CBD.

One shot was fired inside a corporate office on Castlereagh Street just before 1pm yesterday, police alleged.

NSW Paramedics treated the younger man at the scene for a gunshot wound to the groin before he was taken to St Vincent's Hospital in a stable condition.

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The 79-year-old man was arrested by police after being restrained by workers in the office.

Early this morning, police announced he'd been charged with a string of offences including shoot at with intent to murder.

The six other charges relate to alleged weapons offences.

9News understands the alleged shooter was buzzed up to the lawyer's office by the receptionist before the alleged shooting took place.

Police said they were unaware of the relationship between the alleged victim and the alleged shooter but ruled out any gang-related associations.

Police will allege the pair had some kind of personal dispute prior to the alleged shooting.

"This is an isolated shooting, we don't believe it's connected to any gang warfare or anything like that," Detective Inspector David El-Badawi said.

The small-calibre pistol allegedly used in the shooting has been secured by police.

Police advised there was no further ongoing threat to the community.