There are however, legal restrictions around who can collect a TFN and what it can be used for. Section 8 of the Privacy (Tax File Number) Rule 2015: TFN reci

There are however, legal restrictions around who can collect a TFN and what it can be used for. Section 8 of the Privacy (Tax File Number) Rule 2015: TFN recipients must only request or collect TFN information from individuals and other TFN recipients for a purpose authorised by taxation law, personal assistance law or superannuation law. (2) When requesting an individual’s TFN, TFN recipients must take reasonable steps to ensure that: (a) individuals are informed: (i) of the taxation law, personal assistance law or superannuation law which authorises the TFN recipient to request or collect the TFN (ii) of the purpose(s) for which the TFN is requested or collected (iii) that declining to quote a TFN is not an offence (iv) about the consequences of declining to quote a TFN (b) the manner of collection does not unreasonably intrude on the individual’s affairs, and (c) the TFN recipient only requests or collects information that is necessary and relevant to the purpose of collection under applicable taxation law, personal assistance law or superannuation law.