INVESTIGATIONS are continuing into what caused Monday's pile-up on the Oxley Highway near Somerton.
Police said on Tuesday that all factors, including speed and the road conditions, were being investigated as to how five cars and a semi-trailer collided.
Four people were taken to Tamworth hospital after the accident, and paramedics said it was "remarkable" that all involved escaped serious injuries.
The crumpled wrecks of the cars and the truck were strewn across the highway at the crash site, between Somerton and Bective.
Police were interviewing the drivers and the witnesses on Tuesday to determine exactly how it unfolded.
Investigations into the cause of the crash are continuing.Oxley police spokesperson
"Investigations into the cause of the crash are continuing," an Oxley police spokesperson said.
Six ambulances were deployed to the scene, just after 3.30pm on Monday, to treat multiple people.
One of the patients was a 28-year-old man with head lacerations. He was trapped in the wreckage of the truck for a short time before he was rescued.
A 33-year-old male was also treated at the scene for minor head injuries; a 37-year-old man suffered chest pain in the accident; and a 50-year-old man suffered neck pain.
All four patients were taken to Tamworth hospital in a stable condition. Their conditions were unknown on Tuesday.
Ambulance NSW duty operation manager, Inspector Paul McRae, said it was a confronting scene given the number of vehicles involved.
"Remarkably, all patients were transported to hospital in a stable condition," he said.
"Paramedics did a great job responding to the scene and treating all patients efficiently - considering the circumstances, this could have been much worse."
The highway was closed for more than an hour, before it partially re-opened while emergency services cleared the wrecks and debris on the road.