The victory cemented the All Blacks' place as the greatest side in the sport's history and ensured the Webb Ellis Cup would remain New Zealand's property after a third overall triumph.
Nehe Milner-Skudder, Ma'a Nonu and Beauden Barrett all scored tries while Dan Carter booted 19 points on his All Blacks farewell, including a vital drop goal after quickfire replies from Australia's David Pocock and Tevita Kuridrani.
Carter was named man of the match for his contribution, bringing his glittering 12-year, 112-cap career to a glorious end.
All Blacks captain Richie McCaw, another of the game's greats, followed Carter into retirement soon after having earned 148 caps, a record 110 as captain, and lifted the World Cup twice.
New Zealand took an early grip on the game with touchdowns and Milner-Skudder and Nonu helping them into a 21-3 lead.
The Wallabies rallied in the second half and scores from Pocock and Kuridrani brought them back within four points.
Carter put the All Blacks back in control with a superb long-range drop goal and a penalty before replacement Barrett's late breakaway secured victory.