The request reveals the sweeping nature of the probe into how the national broadcaster published top-secret government material containing allegations of misconduct by Australian troops in Afghanistan including the potential unlawful killings of unarmed men and children.

The investigation culminated in a dramatic raid on the ABC's Sydney headquarters last month, triggering a political storm that could lead to legal changes to better protect press freedom.

An AFP statement shows investigators approached Qantas earlier this year asking for information about Daniel Oakes, one of two ABC reporters who broke the story known as 'The Afghan Files'.

The document is dated April 1 this year and headlined "Statement in the matter of R v Daniel Michael Oakes", suggesting police could be building a case against the reporter in addition to pursuing the Defence whistleblower who has already admitted to leaking the information.

It also potentially contradicts an assurance made by Attorney-General Christian Porter last month that there was "absolutely no suggestion that any journalist is the subject of the present investigations".

A Qantas legal officer writes in the document that she received an email on March 15 "regarding a request from the AFP for information concerning the travel bookings of Mr Daniel Michael Oakes".

The officer accessed the internal booking system three days later in search of the two flights, in June and September 2016, that police were interested in.

"This computer system records the bookings and associated passenger details of all individuals who have made travel plans on Qantas and/or Qantas code-share flights," she wrote.

"I captured and printed the booking information and confirmation of travel once received."

The Qantas officer's statement also noted she was prepared to act as a witness in court.

The AFP appeal to Qantas occurred roughly six months after former military lawyer David McBride was arrested for leaking the information to the ABC.

The AFP raided the ABC's Ultimo headquarters a day after searching the Canberra home of News Corp political editor Annika Smethurst over a separate leak of government information.

AFP acting commissioner Neil Gaughan has not ruled out charging journalists or their employers for the publication of confidential documents.

Mr Porter has said he is "seriously disinclined" to authorise the prosecution of journalists. His consent is required before the Commonwealth Director of Public Prosecutions can proceed.

The seeking of journalist flight records will trigger deep unease within Australia's media industry and could force reporters to better conceal their movements given travel bookings might inadvertently help identify a source.

Media chiefs and some politicians have warned the investigations and raids diminish the prospect of future whistleblowers coming forward.

A spokesman for Qantas on Sunday said: "Like all airlines, Qantas receives numerous requests for information from law enforcement agencies and we comply with these requests in accordance with our legal obligations and privacy legislation."

Sources familiar with AFP requests said companies such as Qantas regularly comply in the course of a criminal investigation and would not have been told Oakes was a journalist.

Asked whether the Qantas request related to a possible prosecution of Oakes, an AFP spokesperson replied: "As this investigation remains ongoing, it is not appropriate to comment."

Mr McBride, a former military lawyer and captain in Britain's elite Special Air Service, was arrested in September and charged in late February with theft and three counts of breaching the Defence Act.

Mr McBride had admitted to leaking the sensitive files to the ABC but said he only did so after internal complaints were ignored. He is awaiting trial in the ACT Supreme Court.

In addition to the possible case against Oakes, is was revealed on Friday revealed that Smethurst, a senior member of the Canberra press gallery, could also be prosecuted.

A detective sergeant from the AFP's "sensitive investigations" unit emailed communications staff on the morning after the raid on Smethurst's home to thank them for their service and predict another busy period after a planned raid on the ABC's Ultimo headquarters later that day.

One staff member wrote back: "Reporting hasn't caught up on the publishing offence - many still think she's just doing her job."

The raid on Smethurst's home followed a 2018 report about discussions inside the Department of Defence and Department of Home Affairs about giving Australia's domestic cyber spies broader powers.

Asked last month whether it was a crime to publish leaked secret documents, acting AFP commissioner Gaughan replied: "Yes, it can be", but noted there might be public interest exemptions under federal law.

"I'm not going to rule in or rule out anyone subject to further charges," he said.

A parliamentary inquiry into the impact of national security legislation on press freedom will begin soon and report by mid-October.