According to reports in the Sydney Morning Herald, the ARU have bet $A300,000 ($NZ321,000) on a Wallabies victory to help cover the costs of players' potential win bonuses.
All players in the 31-man squad stand to earn a $A100,000 ($NZ107,000) bonus if they come through against the All Blacks on Sunday, so the windfall from the bet would cover much of the risk of offering the payments.
World Rugby prohibits connected parties from placing bets directly through a bookmaker, so the ARU have avoided any violation by wagering through an insurance company.
"We have an arrangement in place with [Rugby Union Players Association] around player bonuses for the Rugby World Cup, the details of which are in commercial confidence," an ARU spokesman told the Sydney Morning Herald.
Meanwhile, All Blacks players would each take home a $150,000 bonus for winning the final. If New Zealand lose the final and take home the silver medal, their bonus will dip to $35,000 for each player.