A man has been charged following an alleged serious injury crash on the Lachlan Valley Way near Forbes.

A 68-year-old cyclist was airlifted to Sydney's Westmead hospital in a serious condition, after a call at 6.45am Sunday alerted emergency services that a bicycle had been located on the side of the road.

NSW Ambulance paramedics attended and found a 68-year-old man lying in a nearby paddock, NSW Police said.

He was treated at the scene for multiple injuries before being flown out.

Officers attached to Central West Police District and Western Plains Crash Investigation Unit attended and launched an investigation into the circumstances of the incident.

A 35-year-old man was arrested at Parkes Police Station about 1.30pm that day.

He has been charged with dangerous driving occasioning grievous bodily harm – drive manner dangerous and negligent driving (occasion grievous bodily harm), NSW Police said.

Police said inquires indicate that shortly after 6pm on Saturday, 18 April a vehicle was travelling west on Lachlan Valley Way, Forbes, when it has allegedly collided with the bicycle.

The alleged driver has been granted conditional bail to appear at Forbes Local Court on Thursday, 7 May.

As the Advocate prepared for press, Forbes police said the man's condition was reported to be serious but stable.