Two women have been killed and two children have been critically injured in three separate road accidents across the western region on Boxing Day.

Police are investigating the circumstances surrounding the death of a female pedestrian who was killed on the Newell Highway south of Coonabarabran.

The woman died when she was struck by a vehicle early Saturday morning.

In another accident, a 26-year-old woman became the eighth person to die on New South Wales roads this holiday period, when her car collided with two other vehicles near Yass.

Police say the victim died after her sedan hit two oncoming cars on Lachlan Valley Way.

The two drivers of the other vehicles, who are both men, have been treated for minor injuries in Yass Hospital.

Two boys, aged 11 and nine, are also in hospital after their parent’s ute left the Hume Highway and hit a tree near Goulburn.

The children suffered critical injuries, while their mother and father weren’t hurt.