A Tax File Number (TFN) is a unique number issued by the ATO to individuals, companies, trusts, and other entities. It is the primary identifier for income tax purposes: employers use it for PAYG withholding, banks use it to report interest, and superannuation funds use it for member identification.
Privacy and legal obligations
TFNs are sensitive personal information protected under the Privacy Act 1988 and the Tax File Number Rule 2015. Businesses and advisers may only collect, use and disclose TFNs when legally authorised to do so. Misuse carries significant civil and criminal penalties.
Permitted uses for accounting firms
- Preparing and lodging income tax returns on behalf of clients.
- Completing payroll and STP obligations for employer clients.
- Liaising with the ATO, super funds, or Centrelink on a client's behalf.
Storage requirements
Any system that stores TFNs must protect them from unauthorised access. At a minimum, this means strong access controls and audit logging. Best practice is encryption at rest and in transit, with access restricted to authorised staff and a logged record of each reveal.
Accelete encrypts every TFN at rest with AES-256-GCM envelope encryption, and access is gated to authorised firm staff with a per-reveal audit log entry.