The terms of reference for an investigation into the governance and board culture of Australia Post are set to include corporate hospitality and bonuses, with some key players already contacted to provide information to the four-week review.

Chief executive Christine Holgate is fighting to keep her job after it was revealed she spent nearly $20,000 on luxury watches for executives who secured a financial services deal with major banks, well above the $12,000 total price tag she told a Senate committee last week.