In a letter to Attorney-General Michelle Rowland, Mr Lehrmann accused National Anti-Corruption Commission boss Paul Brereton of lacking the confidence of the Australian public.
"The principle at stake is simple: no integrity body can credibly investigate and compel citizens while its own leadership is tainted by unresolved conflicts," he wrote in a letter dated September 12.
Mr Lehrmann was raided by the commission in June 2024.Â
The anti-corruption body was searching for sensitive submarine documents Mr Lehrmann was alleged to have stolen from the office of former defence minister Linda Reynolds.
Mr Lehrmann accused Mr Brereton of a conflict of interest because of his previous association with Ms Reynolds when he was the Defence Department's special investigator.
"The commissioner in this respect appears hellbent on the gratification in targeting me at all costs," he wrote.
He highlighted Mr Brereton's contentious decision not to pursue the principal architects of the failed robodebt scheme in 2024.
An inquiry later found Mr Brereton should have recused himself after declaring a "close association" with one of those referred for investigation by the robodebt royal commission.
The National Anti-Corruption Commission was contacted for comment.
Mr Lehrmann's letter came just days after he commenced legal action in the Federal Court against Mr Brereton and Special Minister of State Don Farrell.
It is the latest in a string of legal proceedings after he was charged with raping colleague Brittany Higgins in Ms Reynolds' ministerial office in 2019.
He has denied the claims, which remain untested in a criminal court after a 2022 trial in the ACT was abandoned because of juror misconduct.
But the Federal Court's Justice Michael Lee found in 2024 the allegations he raped Ms Higgins were proven on the balance of probabilities, which is a lower civil standard of proof than its criminal counterpart.
Mr Lehrmann had sued Network Ten and journalist Lisa Wilkinson for defamation, after her interview with Ms Higgins on The Project in 2021.
Justice Lee found the allegations were likely true in his headline-grabbing judgment, famously quipping: "Having escaped the lions' den, Mr Lehrmann made the mistake of going back for his hat."
Mr Lehrmann's appeal against his defamation loss was heard by a panel of judges in August.
The justices reserved their decision to be delivered at a later date.
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