The identity of a 22-year-old man shot and killed by police in Western Australia after he allegedly threatened an officer with a knife has been released.

Hayden Paul Stacey, the man shot and killed by WA police in Wannanup. Credit:Facebook

Police say they were responding to reports of a man behaving suspiciously in Wannanup just after midnight on Sunday when they spotted him with a knife and he lunged towards an officer, ignoring commands to drop the weapon.

Officers say they tasered the man, which didn't stop him approaching and he was then shot, later dying in hospital.

On Wednesday, police confirmed the deceased man was Hayden Paul Stacey.