This article is sourced from teamdsc.com.au

The National Disability Insurance Agency is capable of removing people who are under the National Disability Insurance Scheme if they are not able to meet the eligibility criteria. With the new NDIS Act, the NDIA may request information from NDIS participants to find out if they are still eligible. 

Around 1250 people are sent eligibility reassessment letters. These letters will inform NDIS participants that an eligibility reassessment has started and explain why. They should also include clear information on what details you may provide. And also, you only have 90 days to provide said information. 
If the NDIS participant fails to provide the requested information, then the NDIA may revoke their access. To further provide clarity for NDIS participants, an NDIS eligibility reassessment factsheet has been provided by the NDIS.