There is strong evidence that a policewoman who shot a mentally disturbed man in the back in 2009 accidentally used her gun instead of her Taser, a coroner has found.

Adam Salter was shot and killed in the kitchen of his Lakemba home in November 2009 after police responded to a call that the 36-year-old was stabbing himself with a knife.

Shooting victim Adam Salter with his sister Zarin.

The shooter, Sergeant Sheree Bissett, and NSW Police claimed that Mr Salter was threatening another officer with a knife and that lethal force was her only option.

But the inquest into Mr Salter's death learnt that Sergeant Bissett shouted "Taser, Taser, Taser" before firing her gun, and Deputy State Coroner Scott Mitchell has found that it was more than likely Sergeant Bissett had made a terrible mistake.