More than $400 million in NDIS payments are being investigated for fraud.
The number of criminal investigations linked to payments from the disability support scheme had risen to 46, up from 38 in April, NDIS Minister Bill Shorten told parliament.
The investigations are being overseen by a fraud task force, set up in October to examine rorts of the scheme.
Since April, an extra $100 million worth of possible fraudulent payments are being looked at by the task force.
"When there is government money, sometimes people - opportunists, criminals, others - become attracted to trying to siphon that money off for their own good, rather than the best interests of participants," Mr Shorten told parliament on Thursday.
"There is an element in the Australian community who were basically taking money from participants, robbing people on the scheme, and sometimes not only in an unethical manner, but indeed in a criminal manner."
The NDIS is on track to be one of the federal budget's biggest expenses, projected to cost more than $50 billion by 2025/26 and overtaking the annual spend on Medicare.
Mr Shorten had previously announced a review of the NDIS in an attempt to rein in spending and reduce fraudulent payments.
