Highway pile-up kills two with children among multiple injured

NSW emergency services closed the Great Western Highway in both directions at Wallerawang, west of the Blue Mountains, while a crime scene was established. It has since been opened in both directions.

Police said five cars collided on the highway at 12.50pm on December 29.

Police allege an eastbound Isuzu D-max - towing a motorcycle trailer - and a westbound Toyota Hilux crashed before the Toyota struck a Hyundai Tuscan causing it to leave the roadway, trapping the occupants while the Isuzu struck a Kia Carnival head on.

A Nissan Patrol - towing a caravan and travelling behind the Isuzu - struck the trailer, police said.

The Isuzu driver, a 42-year-old man, and the Kia driver, a 49-year-old man, were trapped and died at the scene, according to police.

Police said the six passengers of Kia, a 41-year-old woman and five children - aged between five and 15 - suffered varying injuries.

They were treated by NSW Ambulance paramedics before being taken to Westmead and Westmead Children's Hospital.

As of Saturday morning, one child remains in a critical but stable condition, the four others are stable while the woman has since been released from hospital.

The Hyundai driver, a 55-year-old man, suffered multiple fractures and was airlifted to John Hunter Hospital, while his two passengers were also taken to hospital for treatment, police said. They all remain in stable conditions.

The four people in the Toyota and four who were in the Nissan were assessed at the scene. Police said the two drivers, aged 39 and 42, were taken to hospital for mandatory testing.

Officers from Chifley Police District established a crime scene, which was examined by specialist police from the Crash Investigation Unit and an investigation continues into the circumstances surrounding the crash.

A report will be prepared for the Coroner.

Aerial footage at the time showed the cars of first responders, including NSW Rural Fire Service, paramedics and police, lining the highway.

The highway was "expected to remain a crime scene for a considerable amount of time", police said.

The crash site was cleared early on Saturday and police investigations have been completed, according to Live Traffic NSW updates.

All lanes of the Great Western Highway are open, all diversions have been lifted.

A two kilometre stretch of road west from Wallerawang's Barton Avenue was closed following the incident.