Former ABC managing director Michelle Guthrie is taking the broadcaster to court over her dismissal, with sources confirming she will claim the board "had no reason to trigger the termination clause".

Key points: Ms Guthrie was sacked last month, mid-way through her five-year tenure

Ms Guthrie was sacked last month, mid-way through her five-year tenure At the time of her sacking, Ms Guthrie said she was considering her legal options

At the time of her sacking, Ms Guthrie said she was considering her legal options By the end of that week, the broadcaster's chairman Justin Milne had resigned

Ms Guthrie has begun the formal legal process and lodged paperwork at the start of this week.

A spokesperson for Ms Guthrie told the ABC she had lodged a claim with the Fair Work Commission, but did not confirm what damages were being sought.

The ABC also confirmed Ms Guthrie had made a complaint, but according to a spokesperson, "details of the complaint are not a matter of public record".

Ms Guthrie was last month sacked from the position, mid-way through her five-year tenure.

At the time of her departure, then-ABC chairman Justin Milne said directors had resolved it was not in the best interests of the broadcaster for Ms Guthrie to continue to lead the organisation.

He said the board had made the decision in the interest of "the millions of Australians who engage with ABC content every week".

He would not be drawn on exactly what had led to the decision "out of respect" to Ms Guthrie, however when pressed, said her "leadership style" had been a factor.

Sorry, this video has expired Justin Milne has stepped down from his position as chairman of the ABC.

At the time, Ms Guthrie said she felt her termination was unjustified and that she was considering her legal options.

"While my contract permits the board to terminate my appointment without cause and with immediate effect, I believe there is no justification for the board to trigger that termination clause," she said.

"At no point have any issues been raised with me about the transformation being undertaken, the Investing in Audiences strategy, and my effectiveness in delivering against that strategy."

Ms Guthrie was sacked on Monday, September 24, and by the end of the week Mr Milne had also resigned amid accusations he interfered in the broadcaster's editorial independence.

In the days after Ms Guthrie's acrimonious departure, explosive reports in Fairfax and News Limited publications claimed Mr Milne had urged the then-managing director to sack two prominent reporters because the Government "hated" them.