Under section 66 of the Banking Act only APRA-authorised banks can call themselves banks.

As an example of APRA’s powers to protect depositors,  David
Robert Siminton has commenced a 12‑months jail term on a contempt of
court charge initiated by APRA in relation to the operation of the unauthorised
‘bank’ Terra Nova Cache.  Siminton’s ‘bank’ obtained in excess of $5 million from more than 100 depositors.