A large police presence rushed to the scene on Steer Road in Gregory Hills after about 8am and urged the public to stay away from the area, News.Az reports, citing Sky News Australia.
The man was shot at outside World Gym and is believed to have left the scene immediately in a white Toyota Hilux.
Detective Chief Inspector Gretchen Atkins said the man targeted in the shooting was not assisting with inquiries and had an "extensive history" with police.
She said the area had been busy at the time and that it was "very, very fortunate" there were no injuries reported.
She praised the assistance of businesses in the area that helped people shelter during the scary incident.
Two men in black clothing and face coverings and armed with firearms were seen at the scene but are also believed to have fled, according to NSW Police.
An area surrounding the gym was cordoned off.
One man, named Jack who was inside Service NSW at the time, told 2GB's Ben Fordham he heard 10 shots fired in the carpark before those in the building rushed for safety.
"We've pretty much just gone in the back room," he said.
"The doors aren't locked, but we're just waiting for everything to be cleared and for police to come. Pretty scary at 8.30 in the morning.'
"We're in a very safe room back here if anything happened. They just told us we'll stay here until we get full clearance."
Another witness told Fordham they saw "two people with balaclavas on their head" and with firearms.
"Pretty shocked at the start. I didn’t really know what it was. I thought it was firecrackers at the start, and then I actually saw the people coming. And I was like, ‘Okay, so that’s gunfire.’ So I kind of yelled to the people in store to just get inside and hide," he said.
Officers have conducted interviews with witnesses.
Inquiries are being carried out as police work to determine the circumstances surrounding the incident.
