An independent advisor is investigating concerns former ABC managing director Michelle Guthrie raised just days before she was sacked.
The ABC board confirmed on Thursday it decided the investigation was needed on September 23, the same day it concluded Ms Guthrie should no longer lead the national broadcaster.
She was sacked the next day.
Ms Guthrie sent the board a letter on September 21, responding to issues it had raised with her.
In it, she flagged other matters she wanted looked at on a confidential basis. The board hasn’t specified what these were.
Chairman Justin Milne officially removed Ms Guthrie on the morning of September 24, pointing to her relationship with the federal government.
But Mr Milne was himself forced to quit after it was revealed Ms Guthrie told the board he had requested she sack two journalists because the coalition government didn’t like their reporting.
“We are united in defending the independence of the corporation,” the board said in a statement on Thursday.
“We have done our job thoughtfully and with due regard to board process.”
The directors stressed they had fully debated issues presented to ensure editorial independence was maintained.
A spokesman for Mr Milne said he welcomes the inquiry and “looks forward to the facts being established”.
“The inquiry was discussed at a board meeting on September 23 and he voted in favour,” he said.
Federal Communications Minister Mitch Fifield last week ordered his department to investigate recent issues surrounding the management of the ABC.
The investigation remains ongoing.
David Anderson has stepped in as acting managing director, while existing board member Dr Kristin Ferguson is acting chair.