If you had the right to compensation but have not claimed or chose not to claim the NDIS may:


Source:  https://www.ndis.gov.au/participants/compensation-and-your-plan/compensation-not-claimed-or-agreed-give


If you have not claimed compensation


If you have sustained an injury, which has resulted in you applying to the NDIS, you may be entitled  to compensation. If you haven’t taken reasonable steps to claim compensation, the NDIA may require you to do so. If you do not take the steps requested by us, we may take action to claim compensation on your behalf or take over conduct of your existing compensation claim. 


The Compensation Operational Guideline explains this in detail Requiring a participant or prospective participant to take action to claim or obtain compensation


If you have agreed to give up compensation


If you sustained an injury, which entitled you to compensation, and you unreasonably agreed to give up your right to compensation, we may adjust the funding in your NDIS plan to account for the compensation you gave up.


This is explained in detail in the Compensation Operational Guideline, Agreements to give up a right to compensation.