Airport CCTV footage could show what happened between Peter Costello and News Corp journalist

Albanese government minister Jason Clare says Canberra airport CCTV footage could shed light on an incident involving the Nine Entertainment chairman, Peter Costello, and a journalist from the Australian newspaper.

Liam Mendes has accused Costello of assaulting him as he attempted to ask the former Coalition treasurer about Nine’s response to allegations of sexual harassment and bullying at the company.

Costello denies he assaulted Mendes on Thursday and says the journalist fell over an advertising placard as he was walking backwards.

Related: ‘You’ve just assaulted me’: Peter Costello accused of ‘violent behaviour’ by News Corp journalist

The Nine board had been scheduled to meet on Friday and it is understood the airport altercation was added to the agenda. A spokesperson for the network said they did not speak about the board.

The airport incident was filmed by Mendes, who can be heard saying “you’ve just assaulted me” and “it’s all on camera” in footage released by the Australian newspaper on Thursday evening.

Clare, the education minister, said on Friday that the airport would have footage of the incident.

“The journalist there says it did happen,” Clare told the Seven Network.

“I see Mr Costello said that it didn’t happen. There’s CCTV footage I’m sure that the airport has as well. It’s a matter for the airport about whether they release that or provide that to the police.”

Guardian Australia understands that Canberra airport will not be releasing the CCTV footage publicly.

A spokesperson for ACT policing said they had not received any reports regarding the incident by Friday mid-morning.

Costello, who was in Canberra for the opening of the new Nine consolidated bureau in Parliament House, spoke to journalists in the press gallery on Thursday evening. He said “there was no assault”.

“I did not lay a finger or a fist or anything else on him,” he said.

“There was a reporter walking backwards with his phone filming. As I walked past him, he walked back into an advertising placard and he fell over. I did not strike him. If he’s upset about that, I’m sorry. But I did not strike him.

“I wasn’t angry. Just like you blokes here if you’re backing back, and there’s a placard behind you, you can walk into it. I’ve seen it happen a million times. I’ve seen it here at Parliament House a million times – reporters back into the bollards and fall over.”

The federal treasurer, Jim Chalmers, said on Friday it was up to Mendes whether he wanted to take the matter further and for those involved to “explain what has happened here”.

“It’s really important we treat journalists with respect, that journalists are safe in their workplace and if anyone should know that, it should be the chairman of a major media organisation,” Chalmers said.

The federal opposition leader, Peter Dutton, told Channel Nine “other camera angles” could help clarify what happened.

“I’m probably not the best person to ask because Peter has been a friend of mine for over 20 years and I’ve never seen any act of aggression from him,” he said on Friday.

“There are obviously other camera angles which I haven’t seen, so probably best for those that have seen all of that to be able to comment. But the Peter Costello I know is somebody who doesn’t have an aggressive bone of that nature in his body. I hope that the matter can be resolved amicably and we move on. Obviously, when there are cameras around and the rest of it, there’s extra pressure.”

In the footage filmed by Mendes, Costello ignores his repeated attempts to question him over the Nine situation as he follows him through the airport. Mendes falls while filming, although it is unclear from the camera angle why he fell.

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Costello continues to walk past him. Mendes follows Costello into the car park saying “that was quite violent behaviour, Mr Costello” while commenting that Nine journalists approach people in the same way Mendes approached Costello frequently as part of the job.

Clare said on Friday: “My view is that if a journalist asks you a question you stop and answer it, and that’s the simplest way to do it rather than try and run away or say no comment or accidentally knock somebody over.”

The deputy Liberal leader, Sussan Ley, told Seven that she had “known Peter Costello for many years and I’ve never known or found him to be aggressive in nature”.

“There’s different camera angles. I haven’t seen them all. Peter has spoken about it. The journalist has spoken about it,” she said.

“It’s worth remembering that in public life people do need to be respectful, whether they be public figures, journalists, politicians, whoever.”