A prominent boxing coach has been killed following an ambush outside a Sydney gym, in the latest suspected attack linked to organised crime.

Louis Meehan, who is the son of former professional boxer Kali Meehan, died in the car park of the Punchbowl Community Centre in southwest Sydney about 5.50pm on Wednesday.

Acting Superintendent Dean Johnstone told media on Wednesday night the 32-year-old suffered multiple gunshot wounds during the attack.

The shooter was inside a silver Lexus sedan, which has since been found in the nearby suburb of Bass Hill.

There was a significant police presence in the moments following the shooting as paramedics worked to save the man.

He died at the scene.

A dozen children were inside that community centre being given tutorial lessons when the shooting unfolded.

Supt Johnstone said he believed the attack was targeted.

"This is a callous act," he said.

"The implications of this act could have easily endangered other members of the community."

Acting Assistant Commissioner Grant Taylor told ABC Radio Sydney the identity of the victim had not been formally confirmed but police believed they knew who he was.

The shooting may have been related to bikie gang activity, and was separate to other types of organised crime shootings in Sydney in recent weeks, he said.

Meehan was part of the Sydney Roosters' NRL system when younger, playing in the National Youth Cup for the club alongside the likes of current first-graders Braden Uele and Kurt Capewell in 2013.

He played 23 games for the club, but never progressed to the NRL team.

His brother Willis played one NRL game for the Roosters in 2014, and was a highly-touted forward who at one stage compared to Sonny Bill Williams.

But his career also never flourished, and he was sacked by the Roosters after being charged with assault in 2015.

The forward later admitted he had been interacting and working with criminals through his time in the sport.

Both brothers had moved into boxing after their rugby league careers.

Police on Thursday assured the community that officers were on the ground investigating the matter.

The shooting comes after the Minns government announced reforms targeting gangland activity on Sydney's streets.

NSW Premier Chris Minns on Monday said he would table legal changes in parliament including new aggravated offences for gangland conspiracy and attempted murder.

It follows multiple high-profile crimes in Sydney, including the death of 23-year-old Marco Tapia, who was shot dead in September, and Sydney grandfather Chris Baghsarian, who was allegedly abducted and killed in February.

Both cases are believed to have involved mistaken identity.