About 11.25pm (Monday, November 16), a food delivery driver, aged 19, was driving his black Audi A4 when he stopped to make a delivery outside a home on The Grandstand, St Clair.
After delivering the food, he was getting back into his car when he was approached by a man armed with a knife. The armed man reached into the car and pulled him out while threatening him with the knife.
The man got into the Audi and drove away. Officers from Nepean Police Area Command were called and established a crime scene.
The armed man has been described as being Middle Eastern/ Mediterranean in appearance, aged in his early 20s and about 170-175cm tall with a solid build and a beard.
Early investigations suggest the armed man was with another two men who were waiting nearby in a small white hatchback as the robbery took place.