A four-wheel drive towing a trailer collided with a truck in Forbes last week, trapping the driver before he was airlifted to Sydney with serious injuries.

Emergency services were called to Sherriff Street, on the Newell Highway opposite the Clear Street cul-de-sac, about 9.30am last Monday 20 July following reports of a crash.

The 46-year-old driver of the four-wheel drive was trapped in the vehicle before being released by NSW Ambulance, NSW Police said in a statement issued to media.

He was treated by paramedics before being airlifted to Westmead Hospital in a serious condition.

A passenger in the four-wheel drive, a 28-year-old man, was treated by paramedics for minor injuries before he was taken to hospital for further treatment.

The 46-year-old male truck driver was uninjured and taken to hospital for mandatory testing.

Central West Police also attended the incident, beginning an investigation into the circumstances of the crash.

Anyone with information, including CCTV or dashcam footage, is urged to contact Forbes Police or Crime Stoppers on 1800 333 000.