"Justin's going to be tough because he knows a lot about what we're about," Mauger said.
"He knows about our style so he will try and be a bit of a menace and upset us.
"He'll be keen to win as well because he's one of the most competitive guys in world rugby so it's important that we get hold of him early and remind him where he is from."
As predicted the All Blacks have made wholesale changes to face the Baa-Baas.
Full-back Mils Muliaina and wing Doug Howlett are the sole survivors for the non-cap international from the team that routed France, with Tana Umaga and Daniel Carter among the replacements.
Coach Graham Henry has taken the opportunity to blood a host of youngsters including prop Saimone Taumoepeau, scrum-half Jimmy Cowan, number eight Steven Bates and openside flanker Jerome Kaino.
Barbarians: M Rogers (Australia); C Latham (Australia), L Tuqiri (Australia), M Turinui (Australia), S Bobo (Fiji); M Giteau (Australia), J Marshall (New Zealand, capt); B Young (Australia), B Cannon (Australia), F Rautenbach (South Africa), D Vickerman (Australia), A Van Den Bergh (South Africa), S Burger (South Africa), P Waugh (Australia), X Rush (New Zealand).
Replacements: G Botha (South Africa, uncapped), A Lo Cicero (Italy), AJ Venter (South Africa), R Samo (Australia), W Greef (South Africa), G Bobo (South Africa), A Tuilevo (Fiji).
New Zealand: S Taumoepeau, C Flynn, G Somerville, R Thorne, A Williams, J Kaino, M Holah, S Bates, J Cowan, A Mauger, R Gear, M Nonu, C Laulala, D Howlett, M Muliaina.
Replacements: K Mealamu, C Hayman, C Jack, M Tuiali'i, P Weepu, T Umaga, D Carter.