Have a look at this link to the ATO website which explains what to do in the case of a lost or stolen tax file number
https://www.ato.gov.au/Individuals/Tax-file-number/Lost-or-stolen-TFN/
Have a look at this link to the ATO website which explains what to do in the case of a lost or stolen tax file number
https://www.ato.gov.au/Individuals/Tax-file-number/Lost-or-stolen-TFN/