Sio back for Final
It is the only change to the side announced by coach Michael Cheika.
Sio has recovered from an elbow injury and James Slipper, who played in the semifinal win over Argentina, returns to the bench.
Australia, who have had a tough route to Twickenham – having to play England, Wales, Scotland and Argentina – will be in a record-breaking fourth World Cup Final.
However, it will be the first between the Wallabies and the All Blacks.
Matt Giteau, who left the semifinal with a groin injury but has been cleared for Saturday, is the only player who took part in their last Final – when they lost to England in Sydney in 2003.
"This week we've had a strong focus on improving certain areas in our game where we feel we haven't been at our best in the previous matches," Cheika said.
"We still have lots of scope to improve and we'll work on that before this next match against New Zealand."
Australia: 15 Israel Folau, 14 Adam Ashley-Cooper, 13 Tevita Kuridrani, 12 Matt Giteau, 11 Drew Mitchell, 10 Bernard Foley, 9 Will Genia, 8 David Pocock, 7 Michael Hooper, 6 Scott Fardy, 5 Rob Simmons, 4 Kane Douglas, 3 Sekope Kepu, 2 Stephen Moore (captain), 1 Scott Sio.
Replacements: 16 Tatafu Polota-Nau, 17 James Slipper, 18 Greg Holmes, 19 Dean Mumm, 20 Ben McCalman, 21 Nick Phipps, 22 Matt Toomua, 23 Kurtley Beale.
Date: Saturday, October 31
Venue: Twickenham, London
Kick-off: 16.00 [16.00 GMT; 05.00 Sunday, November 1 NZ Time; 03.00 Sunday, November 1 AEDT)
Referee: Nigel Owens (Wales)
Assistant referees: Jérôme Garcès (France), Wayne Barnes (England)
TMO: Shaun Veldsman (South Africa)