On the same day the ABC board decided to sack managing director Michelle Guthrie they also launched an independent investigation into problems she raised with them.
The investigation is being carried out by an external advisor and remains underway, the board said in a statement on Thursday.
The board decided the investigation was needed on September 23, two days after Ms Guthrie sent them a letter responding to issues they had raised with her.
In the letter, Ms Guthrie also flagged other matters that she wanted investigated confidentially. The board hasn't specified what the issues were.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Ms Guthrie was sacked on the morning of September 24, with chairman Justin Milne revealing her relationship with the government was a factor in the dismissal.
But Mr Milne was then forced to quit after it was revealed Ms Guthrie's report to the board included his requests to sack two journalists because the federal government didn't like their reporting.
David Anderson has stepped in as acting managing director, while existing board member Dr Kristin Ferguson is acting as chair.
In the latest statement, the ABC board maintained its position that it has always acted in the best interests of the national broadcaster.
The directors stressed they have fully debated any issues presented to them, to ensure editorial independence is maintained.
"We are united in defending the independence of the corporation," the statement reads.
"We have done our job thoughtfully and with due regard to board process."
Communications Minister Mitch Fifield last week also ordered his department to investigate the recent ABC management issues.
