Irish Autism Action CEO Brian Murnane has been forced to admit the charity has received over €600,000 from the Government - despite claiming it receives "no state funding".
Mr Murnane caused a storm this week when he admitted there was no written budget for 2016.
He claimed budgeting was a "hazardous occupation" for a charity because "you're at the mercy of fundraised income".
A Herald investigation found how the IAA received grants from various government departments, including at least €678,066 from the Department of the Environment between 2008 and 2014.
When contacted, Mr Murnane at first claimed "we receive no state funding," apart from a contribution from the HSE for staff - which he said was "insufficient" to cover the cost.
He also said the charity "received a fixed-term, once-off grant from Pobal", the Irish language body, but added this was not a "perpetual" grant.
However, when put to him the Irish Autism Action (IAA) had received other substantial state grants, he conceded "the information is correct on the grants" having "double checked" the figures.
The Department of the Environment said grants were made under the Scheme to Support National Organisations for seven years, but that IAA did not apply for a new round of funding in July 2014. It is unclear why it did not apply.
Annual accounts for the charity for 2012, showed 6pc of its funding listed under "government grant", while 4pc was under the heading "contract work for HSE".
That year, its total income was just over €1.7m. During the year, the IAA received a grant of €90,000 from the Department of Community Affairs.
"This money was provided under a grant scheme to support national organisations," the accounts said.
The charity conducted assessment and diagnosis of 178 children in 2012, under contract from some HSE regions, according to the report.
The following year, the IAA's accounts said it received €77,083 under a Department of Environment grant scheme.
The same accounts broke down the charity's €1.4m income for 2013, including 6pc listed under "government grant" and 5pc under "HSE contracts".
The last accounts filed with the Company Records Office for the IAA were for the year 2014.
Those accounts don't list a government grant, though the Department of Environment confirmed it was granted €37,303 that year. The charity's income was €969,320, including 5pc from 'HSE contracts'.
The HSE did not respond to questions about its funding of the IAA yesterday.