Girl falls from roof of moving car in NT

A 13-year-old girl has fallen from a mattress placed on the roof of a moving car in the Northern Territory.

The incident occurred near Kalkarindji, in the northwest of the territory, on Sunday night and the victim remains in hospital with serious head injuries, police say.

The girl's mother and a 19-year-old woman were in the car and charges have not yet been laid.

"What they've done was the mattress kept blowing off and they thought it would be a good idea to chuck the girl up there to keep the mattress from blowing down," a police spokesman said.

"The mattress blew off again with her.

"What this is is a lack of judgment."

Any witnesses have been asked to contact CrimeStoppers on 1800 333 000.