Purebred or mixed-breed American Staffordshire terriers have killed at least four people in Australia this year.

On Wednesday 61-year-old Leo Biancofiore was killed and his wife seriously injured by their son's American Staffordshire terrier in the north-eastern Melbourne suburb of Mill Park.

In June, police confirmed a 51-year-old man from Nowra, south of Sydney, had been mauled to death by his Staffordshire terrier after he suffered an epileptic fit. The man's wounds were so severe police were originally treating the death as a potential homicide.

That followed the death of a 72-year-old woman, who was attacked by her American Staffordshire terrier south-west of Sydney in May. Her husband was bitten while trying to save her, but survived.