Criminal Code Act 1983

The description or designation in an indictment of the accused person or of any other person to whom reference is made shall be such as is reasonably sufficient to identify him without necessarily stating his correct name or his address or occupation and if, owing to the name of the person being unknown or for any other reason, it is impossible or impracticable to give such a description or designation, such description or designation shall be given as is reasonably practicable in the circumstances or he may be described as "a person unknown".