A man has died following a single-vehicle crash on Saturday at Manildra.

Just after 1pm, emergency services were called to Henry Parkes Way at Manildra, about 30km east of Parkes, after reports of a single-vehicle crash.

"Officers attached to Central West Police District attended and found a Kia sedan had left the roadway and crashed into a tree," a police statement said.

"A front seat passenger in the vehicle – a man believed to be aged in his 30s – was treated by NSW Ambulance paramedics, however he could not be revived and died at the scene."

The man is yet to be formally identified.

Police say the 40-year-old male driver and a 5-year-old boy seated in the rear were treated at the scene by Ambulance Paramedics before being taken to Orange Base hospital for further treatment.

"A crime scene has been established as police have commenced an investigation into the circumstances surrounding the crash. A report will be prepared for the information of the Coroner," police said.