A passing motorist filmed the horrific aftermath of a fatal crash involving a learner driver at the wheel of his family's car.

The 16-year-old boy was driving a Porsche Cayenne four-wheel-drive through Winston Hills on Sunday evening when he was involved in a head-on collision with a Toyota Aurion, police said.

His father, 45, and younger sister, 12, were also in the car and were taken to Westmead Hospital with non-life threatening injuries.

The Toyota Aurion flipped over and the driver, a man believed to have been in his 30s, died at the scene.