Two children have died following a crash on the Newell Highway just north of Dubbo over the weekend.
Emergency services were called and officers from the Orana Local Area Command established a crime scene around 3:30am on Saturday, after a 4WD and B-double truck collided.
5 people were travelling in the 4WD, including a 4 year old boy, who suffered internal injuries and was airlifted to Westmead Children's Hospital in a serious condition.
The male truck driver was also treated at the scene and airlifted to hospital with serious injuries.
A report will be prepared for the coroner.