Employers must lodge all TFN Declarations received from their employees to the ATO within 14 days of the employee starting work.
With the introduction of Single Touch Payroll Phase 2 (STP2), the following applies in relation to lodging TFN declarations:
If you are already reporting to ATO via Single Touch Payroll Phase 2 you do not need to lodge a TFN declaration as it will be handled by the STP batch submission process.
Essentially, you only need to enter a valid TFN in the Employee Masterfile, and the TFN declaration is handled automatically when the employee is paid, and the subsequent STP batch is submitted to the ATO.
for further reference, see the ATO webpage: Lodging tax file number (TFN) declaration data online | Australian Taxation Office