The Sunday Herald Sun revealed that IBAC has appointed an independent figure, believed to be an ex-judge, to finalise the probe into the stoush between former Victoria Police Chief Commissioner Simon Overland and his deputy, Sir Ken Jones.
The decision was made because the IBAC employs staff from the agency it replaced, the OPI.
A range of concerns are expected to be canvassed during the independent review, including any doubts about the OPI handling of its inquiries into Sir Ken.
The OPI had used phone taps and surveillance to investigate claims stemming from the fight between Mr Overland and Sir Ken.
Ms Hennessy said the "sorry saga" had gone on for a long time and involved multiple agencies, so an impartial investigator was needed.
"The outsider is required, given this matter has involved not just the OPI, but it has links to the highest levels of government," she said.
"The inherent conflicts of interest were always there and I suspect they would be there in the future."
She said the results of any final probe into the 'Overland affair' must be made public.
Premier Denis Napthine said because the IBAC was independent, the government would follow its advice on releasing any reports.
He defended the integrity of the IBAC, set up by the Coalition after it was elected in 2010.
"IBAC is independent. How they run their operations, how they conduct their operations is completely independent of government - that's what the people of Victorian want, that's how it should be, and that's what I will insist upon."
The so-called 'Overland affair' sent shock waves through the police force and the State Government.
Mr Overland had complained to the OPI that he believed Sir Ken had been trying to undermine him.
The OPI had also investigated claims Mr Overland was being undermined by former government staffer Tristan Weston.
The affair and its fallout sparked multiple resignations, including that of then premier Ted Baillieu.
news.com.au 27 Oct 2013