The damaged banknote policy can help you determine the amount of damage that has occurred to your banknote.
The Reserve Bank recommends that people take damaged banknotes to their bank or another authorised deposit-taking institution. Badly damaged and contaminated banknotes need to be forwarded to the Reserve Bank's National Banknote Site (NBS) for assessment.
For further information see Claim Requirements and Redeeming Damaged Banknotes.