Genia's Queensland Reds halves partner, Quade Cooper, is also out of the squad continuing rehabilitation from hip and shoulder operations.
There are no surprises in McKenzie's squad, captained by Michael Hooper and including 25 players who tasted action in the 3-0 series clean sweep of France in June.
Cult hero Nick Cummins is the only notable absentee, effectively replaced by Speight, after his decision to sign a lucrative deal to play in Japan later this year.
Melbourne Rebels lock Luke Jones, who debuted in the second test against Les Bleus, has also been dropped after impressive debuts by Sam Carter and Will Skelton.
Brumbies duo Ben Alexander and Joe Tomane have returned from injuries and are strongly in the mix to start in the Bledisloe opener at ANZ Stadium on August 16, when the All Blacks will strive for a world-record 18 straight test victories.
McKenzie said the familiarity of his squad, themselves on a seven-match streak, would be beneficial. "We've come a long way as a group over the past 12 months and the consistency we're now applying ... is a positive sign we're heading in the right direction," he said.
The Wallabies assemble on August 3 for a week-long Bush2Bledisloe regional road trip across Dubbo, Orange, Bathurst and Penrith.
Wallabies squad
Forwards: Ben Alexander, Pek Cowan, James Slipper, Sekope Kepu, Scott Sio, Tatafu Polota-Nau, James Hanson, Nathan Charles, James Horwill, Rob Simmons, Will Skelton, Sam Carter, Scott Fardy, Scott Higginbotham, Michael Hooper (c), Matt Hodgson, Wycliff Palu, Ben McCalman.
Backs: Nic White, Nick Phipps, Luke Burgess, Bernard Foley, Kurtley Beale, Matt Toomua, Christian Leali'ifano, Tevita Kuridrani, Rob Horne, Joe Tomane, Adam Ashley-Cooper, Henry Speight, Pat McCabe, Israel Folau.
