A man has been charged after a woman was struck and killed by a truck while crossing at an intersection in Caringbah.

Authorities were called shortly after 7.30am to the Kingsway near Port Hacking Road after 26-year-old Illawong woman Danielle McGrath was struck.

She was pronounced dead by paramedics on scene after suffering head injuries, police said.

The truck driver, a 59-year-old Illawong man, was taken to Sutherland Hospital for mandatory testing and was later charged with dangerous driving occasioning death.

Inspector Gary Ford told reporters the driver of the truck was "quite distraught and shaken up" after the incident.

Witness John Michaels told 9NEWS he was the first one on the scene but there was nothing he could do for the woman.

"I was the first one there and the poor girl, there was nothing we could do," he said.

The woman is understood to have been on her way to the train station when she was struck. Investigations are ongoing but it is believed she was crossing at a green pedestrian light.

The Kingsway has now reopened.