Peter Costello, the former chairman of Nine Entertainment, resigned from the board following an incident with a reporter at Canberra Airport.
Nine confirmed his resignation, appointing Catherine West, a former Sky UK executive, as his replacement.
Costello, a former federal treasurer, denies accusations of pushing over journalist Liam Mendes from The Australian.
Video footage on The Australian’s website shows Mendes approaching Costello before falling, but Costello denies any assault, attributing Mendes’ fall to tripping over an advertising sign while walking backward and filming.
Mr. Mendes had reportedly questioned Mr. Costello about allegations of “alleged inappropriate behaviour” at the network, including those involving former senior news boss Darren Wick.
Costello stated that he did not strike Mendes.
In a statement, Mr. Costello also mentioned that he had planned to retire from the board sometime after the Olympics in July or by November at the latest. But he has since informed the board that he had decided to step down sooner than planned.
“The board has been supportive through the events of the last month and last few days in particular,” he said.
“But going forward I think they need a new chair to unite them around a fresh vision and someone with the energy to lead to that vision for the next decade.”
Mr. Costello also faced inquiries regarding claims that Nine chief executive Mike Sneesby requested staff to sign non-disclosure agreements following complaints. Mr. Sneesby has refuted this allegation.
In the statement announcing his resignation, Mr Costello added: “Mr Sneesby has always had my full support as CEO.”
“The company has set up a robust process to investigate historical complaints, which has my full support.
“I believe it will get to the bottom of any unknown issues.”
Catherine West has been appointed as the new chair of Nine Entertainment Company, bringing with her over 30 years of experience in the media and entertainment industry in the UK, Europe, and Australia.
Costello served as Australia’s longest-serving treasurer, holding the position in John Howard’s Coalition government from March 1996 to December 2007, before retiring as the federal Member for Higgins in 2009.