The victim, Ho Ledinh, was at the Happy Cup cafe at Bankstown City Plaza when he was shot dead at point-blank range at about 3.40pm.

Hours after his best friend was gunned down,  59-year-old Van Nguyen remained at the scene showing bystanders photos of Mr Ledinh happy and smiling.

He said Mr Ledinh - a criminal lawyer originally from Vietnam, who once owned the Bankstown cafe where he was shot - was a great man.

The pair had coffee at the cafe on Tuesday morning for about half an hour, before Mr Nguyen bade his friend goodbye.

Several hours later, he got a phone call saying Mr Ledinh had been shot and was dead.

When he returned to the Happy Cup cafe, he found the street cordoned off with police tape, with police standing next to a sheet shielding a body on the ground.

He found the man Mr Ledinh was having coffee with and asked what had happened to his friend of more than 20 years.

"I came out upset, I said 'what happened'," Mr Nguyen said.

"The guy, he was sitting at the table there, he said we had a cup of coffee, we talked, another guy walked past and took a gun out - boom boom boom boom.

"No questions asked."

Mr Nguyen said his friend, who was like a brother to him, has several young children and other adult children.

"It's shocking, because I saw him in the morning. I talked to him in the morning," he said.

A witness, who works nearby, said he was upstairs in his office when he heard four gun shots ring out.

The offender is still at large and could still be armed.

Paramedics attempted to treat Mr Ledinh but he died of his injuries at the scene.

One witness told Nine News he heard four gunshots. "A girl was giving him CPR but he was already gone," he said.

Inspector Brad Thorne told reporters the gunman was last seen on foot on Restwell Street, Bankstown.

"We do believe though from the actions and the way the incident's been described to us at this early stage that it is a targeted attack," Inspector Thorne said. "That's the way it appears at this stage."

Duy Nguyen, who was working across the street, said he heard three shots but thought it was a firecracker.

He told AAP the man was sitting with other people at a table outside the Happy Cup cafe.

"At first no one called out for help when he was shot," Mr Nguyen said.

"From what we were able to see he was on the floor.

"I'm a bit shaken right now, it was scary, it happened opposite us."

The shooting on Tuesday is just a few hundred metres from where Wally Ahmad was shot dead almost two years ago.

The Sydney crime figure died outside the Havana Cafe in Bankstown on April 29, 2016.

Ahmad, a father-of-six, was sitting with two associates outside the cafe when a hooded gunman fired multiple bullets into his back before sprinting away.

The shooting was caught on CCTV cameras.

It was part of a long-running dispute between a group of families in Sydney's south-west.

Police established Strike Force Bindon to investigate the shooting, which remains unsolved.