West Australian police are investigating the death of a 20-year-old man who died in Broome on Sunday.

Police and St John Ambulance staff were called to the home, in the state's Kimberley region, at about 4am (WST) and found an injured man.

He was taken to hospital but died a short time later.

Police have not confirmed what the man's injuries were.

A 20-year-old woman is in custody and is being questioned by police.