Mostert returns after being rested for South Africa’s draw with the Wallabies on Saturday, while Du Preez replaces the injured Jaco Kriel.
The Springboks were dealt a double injury blow in the draw in Perth, with Kriel (shoulder) and Coenie Oosthuizen (broken arm) hurt.
Ruan Dreyer replaces Oosthuizen, while Pieter-Steph Du Toit drops to the bench to make way for Mostert.
“Pieter-Steph did very well when he stepped in for Franco last weekend in a rotational switch,” Springboks coach Allister Coetzee said.
“Franco had five superb matches before he was rested last week, he is refreshed again and I expect another strong performance from him as his high work rate is much needed.
“Ruan did well when he replaced Frans Malherbe against a powerful French front row in June and he will start on Saturday because we want to persist with Trevor Nyakane and Steven Kitshoff as a combination off the bench to make an impact in the second half.”
— South African Rugby (@Springboks) September 14, 2017
New Zealand and South Africa are unbeaten in this year’s Rugby Championship ahead of their meeting at QBE Stadium in Albany.
Coetzee said he was looking forward to the challenge of facing the all-conquering All Blacks.
“They are the number one side in the world both in rankings and experience and there is no greater contest than to play them in New Zealand,” he said.
“The rivalry between the two sides are filled with rich history, and on Saturday we get an opportunity to be part of that. They are always at their best when playing the Springboks and we are expecting another huge battle.
“There are no room for errors against the All Blacks because they will punish you for every mistake. We prepared well for this challenge and we will get another opportunity to gain more valuable experience as we continue to grow as a team.”
South Africa: Andries Coetzee, Raymond Rhule, Jesse Kriel, Jan Serfontein, Courtnall Skosan, Elton Jantjies, Ross Cronje; Tendai Mtawarira, Malcolm Marx, Ruan Dreyer, Eben Etzebeth, Franco Mostert, Siya Kolisi, Jean-Luc du Preez, Uzair Cassiem.