The All Blacks have been boosted by the return to fitness of first-five Dan Carter ahead of their two toughest challenges of the Rugby Championship.
Carter had been ruled out of the last two tests for the All Blacks, against the Pumas in Wellington and Springboks in Dunedin, due to a calf strain, with Aaron Cruden filling the No10 jersey in his absence.
But coach Steve Hansen would have been relieved to have received the news that Carter has been considered fit enough to travel with the All Blacks to Buenos Aires on Saturday and to Johannesburg to play the Boks a week later.
Two long-haul flights and matches against the two of the most physical teams in the world present Hansen's toughest challenge as All Blacks' coach so far. He will be relying on Carter's experience and tactical kicking ability to guide the team in two hostile stadiums against two teams which will have scores to settle.
Hansen said: "Dan is recovering well from his calf injury and we're expecting him to be fit for selection for the Argentinian Test. However, to be on the safe side we're also taking Beauden Barrett as cover at five-eighth, alongside Aaron Cruden.
"As we're only able to take 28 players on tour, to include Beauden we unfortunately have to leave one player behind and the logical choice was for a prop to miss out. In this case, it made sense to leave Wyatt Crockett at home as we can cover all our bases with the other four props," Hansen added.
Argentina competed well in Wellington, although the windy and wet conditions suited them, and they will be fired up to deliver a similar test at Estadio Ciudad de La Plata a week on Sunday (NZT).
The Springboks will also be desperate to prove themselves at Soccer City in Johannesburg after going closer than expected in the 21-11 All Blacks' victory in Dunedin last weekend.
Barrett had been put on standby for the trip due to Carter's injury which is why he didn't play for Taranaki in their defeat to Auckland at Eden Park on Wednesday.
All Blacks' squad to travel to Argentina and South Africa:
Hookers: Andrew Hore and Keven Mealamu. Props: Charlie Faumuina, Ben Franks, Owen Franks and Tony Woodcock. Locks: Brodie Retallick, Luke Romano and Samuel Whitelock. Loose forwards: Sam Cane, Richie McCaw (captain), Liam Messam, Kieran Read, Adam Thomson and Victor Vito.
Halfbacks: Aaron Smith and Piri Weepu. First-fives: Beauden Barrett, Daniel Carter (vice-captain) and Aaron Cruden. Midfielders: Tamati Ellison, Ma'a Nonu and Conrad Smith. Outside backs: Israel Dagg, Hosea Gear, Cory Jane, Ben Smith and Julian Savea.