Australia’s domestic spy agency ASIO has warned the media cannot be exempted from national security laws because there is evidence hostile foreign spies are posing as journalists.

In a classified submission to the press freedom inquiry on Wednesday, the spy agency is understood to have given examples of this activity, including spies trying to recruit Australian journalists and hiding in plain sight as media operatives.

ASIO deputy director-general Heather Cook told a parliamentary inquiry into press freedom that exemptions for journalism could open the door to protection for spies.

“I’d like to make a few comments about our knowledge and awareness of how the profession of journalism can be used nefariously by foreign intelligence services,” she said.

“We know from decades of operational and investigative work that foreign intelligence actors, hostile to Australia’s interests, deliberately structure their activities to take advantage of vulnerabilities in our laws.

“These foreign intelligence actors seek to exploit vulnerabilities in our legal system in order to harm Australia’s security and to recruit individuals who can assist them in their goals.

“In Australia today, journalism is being used as a cover by foreign intelligence actors, and there’s a long history of this worldwide.”

ASIO said the reality of spies posing as journalists or seeking information from media organisations was “not new, novel or exaggerated”.

“Australian journalists have self-reported to ASIO that foreign intelligence actors have sought to recruit them in order to gain access to privileged information or to senior officials,” Ms Cook said.

ASIO said broad exemptions for the media and journalists would invite exploitation by foreign intelligence actors and may increase the intelligence threat faced by Australian journalists.

“The agency has previously pointed to a story by Angus Grigg from The Australian Financial Review about an approach from Chinese operatives. ASIO director-general Duncan Lewis described the story as ‘illuminating’ and ‘stunningly consistent’ with other examples known to the agency,” she said.

Ms Cook also warned media organisations were simply not equipped to make judgement calls about how top secret a classified document was.

“Absolutely. I’m firmly of the view that it would be difficult, if not impossible, for someone not intimately familiar with the intelligence and its origins to be able to make a judgement about the sensitivity of that document,” she said.

Earlier, police revealed they had identified the prime suspect in the leak of top-secret information that led to a raid on the home of a News Corp journalist.

Home Affairs chief Mike Pezzullo said he wants the leaker to “go to jail”.

Mr Pezzullo bluntly told the committee the public servant involved in the leak to Annika Smethurst was playing a “Canberra game” and insisted he or she was “not a whistleblower”.

“Frankly, subject to due processes, they should go to jail for that,” he said.

Brandishing a copy of Ms Smethurst’s “offending” article, Mr Pezzullo said it was the publication of a screenshot of the top-secret document by The Sunday Telegraph that was particularly problematic.

The screenshot, he implied, essentially confirms that a crime had been committed if such a document had been provided to a journalist.

“It is completely unacceptable … for someone to have given the journalist that document. It is a crime,” Mr Pezzullo said.

Australian Federal Police deputy commissioner Neil Gaughan said there was real concern about the suspected leaker and their role in the bureaucracy.

“Particularly with the one we are talking about, there is significant concern around the person who has allegedly provided the information to the journalist,” Mr Gaughan said.

“There is significant concern around where that person potentially sits within the bureaucracy.”

At that point, AFP Commissioner Andrew Colvin whispered to his deputy “just leave it at that”.