A 39-year-old woman has been seriously injured after being run over by a four-wheel drive while sleeping on a beach in Western Australia's far north.

Police said the Broome woman was sleeping in a swag on Cable Beach when she was hit by a Toyota Landcruiser at 3:00am on Sunday.

She had been camping with a group of people.

She was taken to Broome Hospital, but will be flown to Perth for additional medical treatment.

A 56-year-old man is assisting police with their inquiries into the incident.