The CEO of the Anindiliyakwa Land Council has been referred to the National Anti-Corruption Commission (NACC).

Mark Hewitt, the chief executive of Groote Eylandt's Anindiliyakwa Land Council (ALC), is facing increased scrutiny over allegations of the misuse of millions of dollars in mining royalties.

Hewitt also serves as co-chief executive of Winchelsea Mining - raising questions about potential conflicts of interest. 

The company, which operates on Groote Eylandt, received more than $16 million in royalties to support infrastructure development for its manganese project. 

Despite the controversy, Hewitt continues in his role as the head of the ALC and has denied any wrongdoing.

In addition to the NACC referral, the National Indigenous Australians Agency has been conducting an independent review into the operations of the ALC. 

The review was initiated following concerns about the land council's governance, highlighted in a petition to the federal parliament. 

Sean Worth, the Integrity Group manager at the NIAA, said during a senate estimates session that while the review was expected to be completed by July, the recent death of the ALC's long-term chair might delay its release.

Independent Senator David Pocock has described Hewitt's dual roles as a “pretty egregious conflict of interest”.