"The biggest point is that he's played there a lot more than Mala," Hansen said. "He's comfortable there, Mala is still learning to play there. To put him in that situation as a young footballer is probably not fair to Mala and Ryan has played well there whenever he has played for us so we have a lot of confidence in him."
"They'll be pretty good," Hansen said of Crotty and the returning Conrad Smith. "They've had a lot of training time together and they'll complement each other. Obviously [they're] not the same experienced pair as Nonu and Smith, but again, we're very confident that the pair of them will play well together. They're both intelligent players, with good ball skills, both good defenders, both good talkers, both have had experience as captains and leading their franchise teams."
The other change to the starting line-up was the naming of Liam Messam for Jerome Kaino, the big Blues loose forward ruled out with an elbow problem which is likely to sideline him for up to six weeks.
Charlie Faumuina returns from illness to replace Joe Moody as prop cover.
Hansen, who said he had a full and frank conversation with referee Jaco Peyper following the South African's performance in last weekend's 12-12 draw in Sydney, is hoping for a more consistent performance from Frenchman Romain Poite. However, he is also hoping for a lift in intensity from his players.
"We've spoken to the ref about the scrummaging and he's put his hand up and said he got the free-kicks wrong. We can't control him. We've had the discussion we've needed to have and moved on.
"There were quite a few things we had a chat about. It was a good conversation and I respect the man for his honesty. He's no different from the players. Sometimes you have a bad day and he's had a bad day at the office and put his hand up. But I've got to emphasise - it wasn't just his problem. We had a hell of a bad day ourselves.
"There's plenty of criticism that was warranted last week - we didn't play well enough.
We have to be honest about that and if we want to retain the Bledisloe Cup we have to go up about 10 to 12 notches and get into it. The criticism is fair, it's not just the punch in the backline, it's right across the park."
All Blacks start XV to face the Wallabies (tests played in brackets)
1. Wyatt Crockett (28)
2. Dane Coles (19)
3. Owen Franks (58)
4. Brodie Retallick (28)
5. Samuel Whitelock (55)
6. Liam Messam (32)
7. Richie McCaw - captain (128)
8. Kieran Read (63)
9. Aaron Smith (30)
10. Aaron Cruden (33)
11. Julian Savea (23)
12. Ryan Crotty (7)
13. Conrad Smith (78)
14. Cory Jane (49)
15. Ben Smith (30)
Reserves:
16. Keven Mealamu (114)
17. Ben Franks (32)
18. Charlie Faumuina (20)
19. Steven Luatua (12)
20. Sam Cane (15)
21. TJ Perenara (4)
22. Beauden Barrett (20)
23. Malakai Fekitoa (3)