Reports are being prepared for the coroner following fatal crashes near Gilgandra and Grenfell, while a 17-year-old male was flown to Sydney in a serious but stable condition after a single-vehicle crash near Orange.

Police said a man aged in his 80s had died in hospital after a crash near Gilgandra overnight.

Emergency services were called to the Newell Highway, 10km south from Gilgandra, after a truck and a Mitsubishi SUV collided about 6pm on Saturday.

The male driver and female passenger of the SUV, both aged in their 80s, were treated at the scene by NSW Ambulance paramedics before being taken to hospital.

The female passenger was taken to Dubbo Hospital for treatment while the man later died in hospital.

The truck driver, a 59-year-old man from Benalla, Victoria, was uninjured. He was taken to Gilgandra Hospital for mandatory testing.

Officers from Orana Mid-Western Police District attended and are investigating the circumstances surrounding the crash.

Earlier, emergency services were called to the Mid-Western Highway, about 30km west of Grenfell, after reports a truck carrying a load of gyprock had hit a tree and caught fire about 5.20pm.

The driver and sole occupant, a 43-year-old Kariong man, died at the scene.

And a 17-year-old man is in a serious but stable condition in Sydney's Westmead Hospital after coming off the road in a single-vehicle collision about 10 kilometres north of Orange on Saturday morning.

Another driver found the man's car off the side of the road at about 6.50am on Saturday and called emergency services, who responded to find the man trapped in his vehicle

Anyone with information about any of these incidents is urged to contact Crime Stoppers: 1800 333 000 or report it online here.

Information is treated in strict confidence. The public is reminded not to report crime via NSW Police social media pages.