Chief commissioner of the NSW corruption watchdog, John Hatzistergos, says he is a "strong supporter" of public hearings by integrity commissions, as they boost transparency and accountability.
The Albanese government's proposed National Anti-Corruption Commission is being examined by a joint parliamentary committee, with public hearings being held in Canberra this week.
The anti-corruption body is set to cost $262 million over the next four years, would operate independently of the government, and have powers to investigate serious or systemic corrupt conduct across the commonwealth public sector.
A major issue raised by the crossbench is the high threshold for public hearings, which under the government's bill would only be held in "exceptional circumstances".
Giving evidence on Wednesday, Mr Hatzistergos said under his state's Independent Commission against Corruption model, public hearings helped investigations as people were encouraged to come forward and provide additional information.
"I'm a strong supporter of public hearings. I believe they make the organisation (integrity commissions) accountable ... it also ensures transparency for the agency," he told the committee.
"If it's all done in private, I would have concerns about it."
When asked if former politicians should be barred from being appointed as the body's commissioner, Mr Hatzistergos who is a former NSW attorney-general and District Court judge, said he didn't have a view on this question.
He pointed to the NSW body which had scope to investigate the judiciary, and said under that threshold, judges would be excluded from being appointed as well.
The commissioner for South Australia's corruption body Ann Vanstone said she had only ever seen one "vexatious complaint" brought before the commission, which was "extremely rare".
Ms Vanstone said any suicide that happened after a person came under investigation by the commission was a "tragedy" and backed providing mental health support for people subject to scrutiny.
"These are dreadful events ... but it doesn't mean that we shouldn't have investigated what they did," she told the committee.
She also said investigations should continue to take place, even if they did not result in a conviction.
Hearings will continue this week, with the committee to report back by November 10.
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