At about 7.45pm overnight, police were called to Carlisle Avenue in Mount Druitt.

They found a 57-year-old man, a pedestrian, with life-threatening injuries.

He was carrying a one-year-old child at the time of the collision.

The man was treated by paramedics but died at the scene.

A short time later, a man believed to be the infant’s father arrived at Mount Druitt Hospital with the child.

The child was taken to Westmead Children’s Hospital in a critical condition.

The driver of the car, a 37-year-old woman, was taken to hospital for mandatory testing and is assisting police with inquiries.

An investigation is underway and a report will be prepared for the coroner.

Anybody with information or dashcam footage is urged to contact Crime Stoppers on 1800 333 000.