A man has sustained serious injuries and is recovering in hospital after a hit-and-run east of Melbourne, police say.

The man, in his 40s, was pushing his bike along Healesville-Koo Wee Rup Road, near Paperbark Road at Yellingbo, just after 10.30pm (AEDT) on Friday, when a vehicle hit him, police say.

The driver failed to stop to the scene.

The injured man was flown to Royal Melbourne Hospital, where he remains in a serious but stable condition.

Police are appealing for witnesses to the incident and, in particular, a man who stopped to assist the injured man contact police.

Anyone with information is urged to call Crime Stoppers on 1800 333 000.