Weepu, who many consider lucky to make the All Blacks squad at all after he returned to Super Rugby overweight and unfit, has been used solely as a replacement this season behind rookie Aaron Smith but will start in Dunedin.
Smith has been preferred by Hansen due to his speed of pass that has given the All Blacks more space and time, but he struggled against a physical Argentina side last week in Wellington.
Weepu came on as a second-half replacement and his experience settled the All Blacks as they adopted a more conservative approach in the atrocious conditions, going on to grind out a 21-5 victory.
The scrum-half was the only change to the backline but Hansen made three alterations to his pack, with Sam Whitelock replacing Brodie Retallick at lock, Liam Messam coming on to the blindside of the scrum for Victor Vito while hooker Andrew Hore replaces Keven Mealamu.
Retallick, Vito and Mealamu all drop to the bench for the match at Otago Stadium.
Hansen's only other change on the bench was to bring utility back Tamati Ellison in for Ben Smith, who had covered the outside backs for the three earlier matches in the expanded southern hemisphere tournament.
"At the halfway stage of the... Rugby Championship we are very happy, from a results point of view," Hansen said in a statement of New Zealand's perfect record to date.
"There is a second challenge we have set ourselves, to constantly improve our game and in that regard we are not the finished product. However, the coaching staff and team leaders are reasonably happy with the progress we are making."
New Zealand: 15-Israel Dagg, 14-Cory Jane, 13-Conrad Smith, 12-Ma'a Nonu, 11-Julian Savea, 10-Aaron Cruden, 9-Piri Weepu, 8-Kieran Read, 7-Richie McCaw (captain), 6-Liam Messam, 5-Sam Whitelock, 4-Luke Romano, 3-Owen Franks, 2-Andrew Hore, 1-Tony Woodcock
Replacements: 16-Keven Mealamu, 17-Charlie Faumuina, 18-Brodie Retallick, 19-Victor Vito, 20-Aaron Smith, 21-Beauden Barrett, 22-Tamati Ellison
- Victor Vito
- Brodie Retallick