Hunt for gunman who gunned down well-known lawyer in busy Sydney shopping mall

A major manhunt is underway for a gunman who opened fire in a terrifying street murder in Bankstown on Tuesday afternoon.

A crime scene stretching several hundred metres remains in place around Old Town Plaza in Sydney's southwest.

Seven News can reveal the victim is a well-known lawyer gunned down in what appears to be a targeted attack.

Ambulances arrive at the scene of the shooting. Source: 7 News

Next to racks of clothes and empty cafe chairs, afternoon shoppers became witnesses to a murder.

"A guy pulled out his gun, shot him four times in the stomach, I don't know where he went," one witness said.

Standing in shock, dozens of people were pushed back as police unravelled their tape to lock down the crime scene.

Police talk to shocked witnesses at the scene. Source: 7 News

The bullets rang out at 3.40pm on Tuesday afternoon and the victim, aged in his 60s, was confirmed dead within the hour.

He was shot outside the Happy Cup Cafe, close to the busy Bankstown Train Station and an entrance to the Bankstown Sports Club.

Witnesses say the victim tried to run, but collapsed after being peppered with bullets.

Police cars and ambulances attend the scene. Source: 7 News

Ambulances and police cars were on the scene within minutes but the gunman had already fled.

The police helicopter is searching from the air, with support on the ground.

The crime scene remains in place on Tuesday night, with police narrowing down the description of the person who pulled the trigger.

Security footage shows a man in a fluorescent yellow vest and baseball cap. Source: 7 News

Seven News has obtained security video allegedly showing the gunman on his way to the shooting.

Witnesses told 7 News a man wearing a high-vis shirt captured on CCTV is the suspected gunmen.

The footage was seized by police moments after it was filmed, but NSW Police would not confirm any details of the possible shooter.

The Bankstown Train Station remains open but authorities are warning to expect major delays as police continue to investigate the crime scene.

Anyone with information is encouraged to call Crime Stoppers on 1800 333 000 or report anonymously online.