Paul Brereton, the former judge who was meant to clean out corruption in federal politics and the public service, resigned on Monday before publication of an investigation into his own conduct.

The National Anti-Corruption Commissioner said he would leave the agency he has led since its creation three years ago. Denying he had done anything wrong, the Army Reserve general acknowledged that he was under scrutiny over allegations of conflict of interest.

The government has received a draft report into his conduct by Gail Furness, a lawyer who handles complaints about the commission.

Maj-Gen. Brereton was due to appear before a Senate committee this week, where he would have faced tough questions from the Coalition and Greens. Remaining in the position until July 6, it is unclear if he will turn up with other members of the commission.

Critics have been unhappy with the limited number of investigations completed by the commission, its reluctance to hold public hearings and pursue the “Robodebt” affair, and Maj-Gen. Brereton’s unpaid, freelance help to the Office of the Special Investigator, the agency investigating former SAS soldier Ben Roberts-Smith and other veterans accused of executing prisoners.

Maj-Gen. Brereton’s four-year investigation into the Afghanistan war, conducted while he was a judge on the NSW Supreme Court, was praised by supporters as a turning point in the pursuit of justice for Afghans and condemned by critics as a heavy-handed attack on veterans that complicated prosecutions by compromising evidence.

‘It is time’

“While I will continue to resist any suggestion of impropriety, I have decided that it is time, now that the Commission is established and functioning with quality staff and good processes, to step aside and allow a new Commissioner to lead it into the next phase of its development into a key and respected component of the integrity architecture of the Commonwealth,” Maj-Gen. Brereton said in a statement published on the commission website.

A spokesman for Mr Roberts-Smith declined to comment.

The resignation was met with relief by some of the organisations and political leaders who led arguments for the creation of a national anti-corruption body during the 2022 election campaign.

“I have called for some time for Commissioner Brereton to step aside and I welcome his decision to do so today,” independent ACT senator David Pocock said. “There have been too many perceived conflicts of interest, too many decisions out of step with community expectations and the need for the NACC Inspector to intervene too many times.”

Greens senator David Shoebridge, who emerged as a leading critic of the former judge, accused him of an “inability to appropriately manage conflicts of interest” and said his resignation was “the right outcome”.

Even anti-corruption group Transparency International Australia complained the commission “has been clouded in perceptions of conflict of interests” and should build “a better relationship with the public”.

Complaints from both sides

The commission’s creation was heralded as a turning point in fighting high-level corruption after nine years of Coalition governments. Independent MPs known as teals had promised to “clean up Canberra” through the NACC.

But the agency mostly investigated run-of-the mill complaints, including a procurement manager at Western Sydney Airport who was sentenced to 500 hours of community service for seeking a $200,000 bribe.

Conservatives became unhappy with the commission’s decision that there was nothing wrong with a $2.4 million payment to former press secretary Brittany Higgins, who alleged she was raped in a ministerial office in 2019.

On the left, the commission was criticised for initially refusing to investigate a computer-driven scheme that pursued welfare recipients for repayments known as Robodebt. When the commission gave in to public pressure, it found two public servants had behaved corruptly and cleared former prime minister Scott Morrison. No one was charged.