Emergency crews have freed a young man who was impaled by a piece of steel in a freak accident on a Sydney construction site.

The 19-year-old man was working on some machinery at the Lindfield site when he was struck in the face, around 10 o'clock this morning.

He was inside the cabin off an excavator, breaking concrete, when a piece of reinforced metal pierced through the floor of the excavator, and became lodged between his eyes.

View photos Paramedics work to free the 19-year-old man who had been working on a townhouse development on Sydney's north shore. Photo: 7News More

The fire brigade freed the man, who was conscious and alert the entire time, and was talking to his rescuers.

The man said he was in pain, but was very brave and "didn't moan too much", according to emergency workers.

"He was exceptionally calm for having the injury that he sustained, or visibly sustained he was calm, he didn’t make any noises, we told him what we were doing," station officer Greg Pace told 7News at the scene.

"It was a delicate situation, crews got out some gear to prepared to cut the rod, but the doctor said no 'we'd prefer to move him with the rod in-situ so as to reduce the vibration,'" Pace said.

View photos Emergency crews are working to free a young man impaled by a piece of steel on a Sydney construction site. Photo: 7News More

The young man was seen holding onto the pole, and moving both arms.

An ambulance doctor was flown to the site and paramedics monitored his condition.

He is currently in a stable condition at Royal North Shore Hospital.

MORE details in 7News at 6pm...