A family is grieving and a tight-knit religious community is in shock after the death of two young children in a head-on collision in Melbourne's west. The children have been identified as Ruana and Immanuel George.

Police said on Tuesday evening that they had charged a man over the fatal collision.

The children were travelling home with their parents from a birthday celebration when a Ford Territory attempting to overtake another car collided with their Ford Focus on Hopkins Road in Truganina in the early hours of Sunday.

The driver of the Ford Territory, a 41-year-old Rockbank man who remains in hospital, was charged with negligence causing serious injury and two counts of culpable driving.

Ruana, 10, was killed at the scene. Her father George Panicker, mother Manju Varughese and brother Immanuel George, 4, were rushed to hospital.