The former attorney-general’s legal action has cost the ABC about $780,000 so far. 

Ex-AG Christian Porter recently dropped his defamation case against the ABC and journalist Louise Milligan over a story about an unnamed Cabinet Minister accused of a historical rape allegation.

Days after the story was published, Mr Porter named himself as the minister in question but strenuously denied the claim. The case ended after a settlement was reached.

ABC managing director David Anderson says the public broadcaster will cover Mr Porter's mediation costs of about $100,000, but no damages would be paid.

Speaking at a Senate Estimates hearing this week, Mr Anderson revealed the total cost of defending and settling the case so far is about $780,000.

Mr Anderson said the ABC went into mediation “to minimise costs”, as a trial would have been far more expensive.

“If it was to be a three-week trial, we think that could have been another $1 million to $1.5 million,” he said.

Both the ABC and Mr Porter have given differing accounts about the matter, with Mr Porter characterising the settlement as a victory for him and a “humiliating backdown” for the ABC.

Mr Anderson said the broadcaster had not backed down, evidenced by the fact that the story is still online.

“The ABC has not issued an apology, the ABC stands by its journalism, the article in question remains online, it remains unchanged and available for everyone to see it,” he said.

There are also reports of internal wrangling over an upcoming episode of the ABC’s Four Corners, which allegedly links Prime Minister Scott Morrison to members of an extreme fringe conspiracy group.