Twenty investigations with an estimated value of $9.3 million are under way into alleged fraud against the National Disability Insurance Scheme.
The figure was revealed in an auditor-general report released on Tuesday into fraud controls managed by the National Disability Insurance Agency.
The NDIA is set to receive $20.2 billion in 2019/20 as it seeks to provide 460,000 people with permanent and significant disabilities with funding for support and services.
The audit found the NDIA is "largely compliant" with federal anti-fraud rules and has a range of strategies to deal with it.
But improvements, which the NDIA has accepted, are needed including better data analytics, project management and reporting to the executive leadership team and board.
A fraud task force was set up in July 2018 and made its first arrest just three months later.
In May this year, it was announced an investigation into an organised criminal syndicate suspected of defrauding the NDIS had resulted in the arrest of five people in western Sydney.
It is alleged that three registered NDIS providers controlled and exploited by those arrested fraudulently claimed more than $1.1 million in payments from more than 70 people with disabilities.
Investigations into the true scale of this fraud are continuing, with the three entities believed to have received more than $2.6 million in NDIA payments since December 2017.
The audit report said between August and December 2018, breaches totalling $4.6 million were identified and $2.4 million was reinstated to participant plans.
