The Australian reporter Liam Mendes had attempted to question Mr Costello at Canberra Airport on Thursday over allegations of harassment at Nine.

Mr Costello is adamant he did not assault the journalist.

“I walked past him, he walked back into an advertising placard and he fell over,” he told reporters later on Thursday.

“I did not strike him.

“If he’s upset about that, I’m sorry, but I did not strike him.”

In a video published by The Australian, Mendes follows Mr Costello through the airport as he asks about Nine chief executive Mike Sneesby.

Mr Costello appears to walk towards the reporter at one point before he falls backwards.

“You have just assaulted me,” the journalist says in the video.

No complaint has been lodged with police over the incident.

The Nine boss was appointed in 2016 after a career in politics where he served as the federal treasurer under Liberal prime minister John Howard.

Asked about the incident, Education Minister Jason Clare said it was a matter for the police but said everyone should be safe at work.

“My view is that if a journalist asks you a question, you stop and answer it,” he told Seven’s Sunrise program on Friday.

“That’s the simplest way to do it, rather than run away or say ‘no comment’ or accidentally knock somebody over.”

Opposition Leader Peter Dutton said he hoped the journalist was okay.

“Peter’s been a friend of mine for over 20 years and I’ve never seen any active aggression from him,” he told Nine’s Today show.

“There are obviously other camera angles, which I haven’t seen.

“But the Peter Costello I know is somebody who doesn’t have an aggressive bone of that nature in his body.”