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

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

MAP: The area where the first crash occurred ...

Officers from the Hume Police District established a crime scene and were investigating the circumstances surrounding the crash.

A report will be prepared for the the Coroner.

Less than an hour later, a emergency services were called to the Newell Highway, about 10 kilometres south of Gilgandra, after a truck and a Mitsubishi SUV collided.

MAP: The area where the second crash occurred ...

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

At about 8.45pm, police were told the male driver had died in Gilgandra hospital.

The female passenger was taken to Dubbo hospital for treatment, while 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 were investigating the circumstances surrounding the crash.

A report about the crash will be prepared for the information of the Coroner.

Anyone with information about the crashes, or who has dashcam vision, is urged to contact Crime Stoppers on 1800 333 000 or at www.nsw.crimestoppers.com.au.

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