A man was found dead at the side of a highway in what is believed to have been a hit and run overnight during a horror 24 hours on WA roads.

Police responded shortly after midnight after a man's body was seen on the Leach Highway at Bateman and when they arrived found a man believed to be in his 40s.

Police believed the man may have been hit by a semi-trailer truck.

A 22-year-old man was killed and two people received serious injuries when their car lost control and rolled in in an accident near Halls Creek in the Kimberley region.

The Toyota camper van, lost control and rolled into a bush, ejecting the male driver, who died, while a 19-year-old woman and 22-year-old man were taken to Broome Hospital on Wednesday.

AAP