The Albanese government will likely be forced to cough up confidential documents relating to its decision to block Qatar Airways from flying extra routes.
The opposition, the Greens and independent senator David Pocock are all pushing for more information about why the government denied the extra flights after being lobbied by Qantas.
Nationals senator Bridget McKenzie has given notice that on Monday she will move for the release of documents provided to the transport minister relating to Qatar Airways' application or advice that helped the minister make her decision.
The bloc would have the numbers for the vote to succeed, but the government can still refuse to produce the documents on certain grounds.
The decision has come under scrutiny after it was revealed Qantas lobbied the government against allowing the extra flights, before posting a record $2.5 billion profit.
Senator McKenzie accused the prime minister of "running a protection racket" for Qantas boss Alan Joyce.
"Release the advice so that this ambiguity and obfuscation doesn't continue," she told Sky News.
The boss of Virgin Australia has also questioned the decision to block more domestic competition to protect Qantas profits, saying the government hasn't been properly informed.
Jayne Hrdlicka said she had sought a number of meetings with the government, but hadn't heard back.
"You got the entire industry (supporting this) and Qantas is the only party objecting," she told ABC Radio.
"We would encourage reopening this ... there wasn't enough information provided to help balance out."
But Qantas executives refuted claims from Ms Hrdlicka that airfares would reduce by at least one-third if there were more Qatar Airways flights added to the market.
Qantas general counsel Andrew Finch told a parliamentary inquiry into competition there was no way of knowing how the entry of Qatar would affect airfares.
"The reality is that no one has any idea what the counterfactual would look like if Qatar had been given permission to add the capacity that it had sought through the government," he told the committee on Tuesday.
Mr Finch also denied it was a responsibility of the government to keep the Flying Kangaroo profitable.
"The role of the federal government is to ensure a level playing field and competitive environment," he said.
"We don't see it as the government's role to keep us profitable or any player in the market profitable."
Prime Minister Anthony Albanese said the decision made by his transport minister was "nothing unusual".
He said past governments had knocked back aviation requests, and Australian airlines "can't fly to where they want, when they want".
"In Australia, we have the most open aviation system in the world bar none," Mr Albanese said.
However, he was tight-lipped about the reasoning behind the decision, with Transport Minister Catherine King only saying it was "in the national interest".
Opposition finance spokeswoman Jane Hume said it was "quite confronting" that Qantas heavily lobbied the Albanese government to deny Qatar the extra flights, and that it then went against departmental advice to take the national carrier's side.
"That in itself is a great concern because it means that the government is actually artificially keeping airfares high," she told Seven's Sunrise program.
Qantas also revealed the value of flight credits it holds is $100 million higher than the $370 million reported, and there are about $100 million in credits yet to be redeemed by Jetstar customers.
Senator Pocock said the credit situation was concerning given Australia's generosity in bailing out the airline during the pandemic.
"Off the back of that they are now making huge profits. I would expect they are also looking after Australians," he said.