A MAJOR police operation placed a residential street in Sydney's southwest into lockdown as armed officers surrounded the scene.

Police were called to Park Avenue in Punchbowl about 3pm over reports a man had been assaulted.

Accompanied by a $400,000 Bearcat armoured vehicle, police from Bankstown and Campsie surrounded a home on the street.

Heavily armed police including riot squad officers established a perimeter, blocking off nearby streets, but found the house empty.

It's believed a victim was assaulted and detained inside a home on the street, before escaping and telling police, according to the Daily Telegraph.

NSW Police confirmed the raid is not terror-related.

They said the people involved in the alleged assault were known to one another.

An investigation is ongoing but no charges or arrests have been made.

Meanwhile, police are investigating a shooting in Bonnyrigg on Tuesday night, in which four homes were shot.

About 8.30pm, several shots were fired into four different homes on Katinka Street, Bonnyrigg.

Three of these homes are neighbouring to each other.

There was also a parked vehicle which was shot.

Police believe one of the homes was the main target of the offenders.

All the home were occupied at the time, but nobody was injured in the incident.

Police from Fairfield Police Area Command were notified of the incident about 5.30pm yesterday.

Crime scenes were established at the four homes which continue to be forensically examined.

Inquiries into the incident continue.