The ABC will be hauled back before Senate estimates to discuss details of its agreement with Christian Porter that led the industry minister to drop his defamation suit against the broadcaster.
The Senate communications committee will hold a hearing as early as next week at which the ABC managing director, David Anderson, will be asked who proposed the settlement and why the public broadcaster agreed to it.
The hearing could seek to expose details of the deal that have so far remained confidential, including mediation costs to be paid by the ABC.
On Wednesday, Guardian Australia revealed Porter first approached the ABC with an offer seeking a modest financial settlement, before he agreed to drop the defamation action in return for a clarification of the intent of the story and costs for mediation.
Porter has sought to portray the outcome as a victory, despite failing to secure an apology, a retraction from the public broadcaster or any damages.
Guardian Australia has been told three senators on the committee – the Greens senator Sarah Hanson-Young and Labor’s Nita Green and Catryna Bilyk – have co-signed a letter to convene the additional estimates hearing.
Three signatories is enough to compel a fresh hearing. The committee will meet on Thursday to set a date.
Hanson-Young, the committee’s deputy chair, said after withdrawing his defamation proceedings “Christian Porter made claims about the ABC which they have refuted”.
“This has raised more questions that need to be answered,” she said on Wednesday.
On Tuesday, Guardian Australia reported that George Christensen complained of ABC bias in the Coalition party room and suggested the government should “strike while the iron is hot” including moving against the ABC chair, Ita Buttrose.
Hanson-Young said the comments were “alarming” and amounted to “demanding retribution against the ABC through funding cuts and an attack on the ABC chairwoman”.
“The prime minister needs to reject any attack on the chair who is independent of government and must remain so,” she said.
Anderson gave evidence at Senate estimates last week before the settlement was reached in the Porter case and made public on Monday.
Porter sued the ABC and investigative journalist Louise Milligan over an article reporting that an unnamed senior minister was accused of raping a 16-year-old in 1988 when he was 17. Porter denies the allegation.
In the aftermath of the settlement, Porter and the ABC engaged in a series of back-and-forth jabs over its terms.
Despite the agreement being confidential, comments by both Porter and Milligan have raised significant questions about the timing and circumstances of the out-of-court deal.
At his press conference on Monday, Porter said the ABC had approached his lawyers “last Friday” for “an urgent mediation”.
“We agreed, we consented to go to that mediation. That mediation was requested by the ABC,” he said.
That timeline was disputed on Twitter by Milligan who wrote that it was Porter who had “proposed a settlement first”. “If he wants to dispute that, happy to refresh his memory and release the terms he offered,” she wrote.
The Greens, Labor and friends of the deceased complainant renewed calls for an independent inquiry into the allegation.
In Australia, the crisis support service Lifeline is 13 11 14. If you or someone you know is impacted by sexual assault, family or domestic violence, call 1800RESPECT on 1800 737 732 or visit www.1800RESPECT.org.au. In an emergency, call 000. International helplines can be found via www.befrienders.org.