The Highlanders star has featured in all six of New Zealand's test matches this year, but has been relegated to the bench by coach Steve Hansen for Saturday's clash.
Rugby Championship: All Blacks drop star scrum-half Aaron Smith for discipline breach
New Zealand have dropped first choice scrum-half Aaron Smith ahead of Saturday's Rugby Championship match with South Africa for disciplinary reasons.
The 23-year-old Highlanders star has been sidelined for the game - one of four changes made by coach Steve Hansen.
Hansen said Smith, who has started in all six tests played by New Zealand this year, needed to be disciplined - but declined to elaborate why.
"Unfortunately for Aaron Smith we've got a strong focus on recovery and he broke a protocol in that area last week, so that made him ineligible for selection for the first XV," Hansen said.
"There's nothing to elaborate on. He just broke a protocol that's non-negotiable and the consequence is you don't start in the XV if you break it."
Smith's demotion earns a recall for 62-Test veteran Piri Weepu, following his impressive substitute's performance last week against Argentina.
The other changes to the side which beat the South Americans 21-5 see lock Sam Whitelock, flanker Liam Messam and hooker Andrew Hore promoted to the starting line-up.
Following the relegation of Smith to the bench, Hansen warned no one in the team could rest on their laurels - despite the All Blacks being unbeaten in the competition.
"At the halfway stage of the new Rugby Championship we are very happy, from a results point of view," he said.
"There is a second challenge we have set ourselves — to constantly improve our game — and in that regard we are not the finished product."
The return of Messam is not a surprise after Hansen rated him the leading blindside flanker. He gave Victor Vito a start last week while Brodie Retallick did not make the most of his start against Argentina and slips behind Whitelock.
Among the replacements, Charlie Faumuina keeps out Ben Franks as the back up prop and Tamati Ellison takes over from Ben Smith in the back utility role.
New Zealand team: Israel Dagg, Cory Jane, Conrad Smith, Ma'a Nonu, Julian Savea, Aaron Cruden, Piri Weepu, Kieran Read, Richie McCaw (c), Liam Messam, Sam Whitelock, Luke Romano, Owen Franks, Andrew Hore, Tony Woodcock.
Replacements: Keven Mealamu, Charlie Faumuina, Brodie Retallick, Victor Vito, Aaron Smith, Beauden Barrett, Tamati Ellison.
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