The All Blacks will take out valuable World Cup insurance by starting young playmaker Aaron Cruden against the Wallabies in the final Tri-Nations Test on Saturday week.

Coach Graham Henry called up Canterbury five eighth Colin Slade as the replacement for injured superstar Dan Carter in his 26-man squad for the Test at Sydney's ANZ Stadium.

But he confirmed 21-year-old Cruden would definitely get the starting five eighth role after playing occasionally from the bench as Carter helped secure the Tri-nations Title and Bledisloe Cup for all-conquering New Zealand this season.

Cruden has made five appearances off the bench for New Zealand this season and takes the goalkicks for Manawatu in the national provincial championship, but it may be asking too much for such an inexperienced player to assume those duties at test level.

Henry said Carter's injury might be a blessing in that it allowed Cruden to get a start against strong opposition.

The All Blacks are gearing towards next year's home World Cup, when Carter will be a pivotal figure and Kiwi fingers will be crossed that he gets through unscathed.

"In hindsight we probably should have played him (Cruden) against Wales in Hamilton (in June) in that second Test, but we went through a few negative times last year and we didn't want to risk anything," Henry said.

"This is a great opportunity for him. It's a big Test match played away from home in Sydney.

"It's always been a difficult place for us to play ... so the team's going to be under pressure and it's a good challenge for him."

Henry said Slade was chosen as back-up for Cruden ahead of candidates such as Canterbury teammate Stephen Brett and North Harbour's Luke McAlister because he was the form first five-eighth at provincial level.

Henry has stayed true to the core of his team who are unbeaten this year, including five-from-five Tri-Nations wins to seal that competition a month before its completion.

Australia have won one from four Tri-Nations Tests and face South Africa in Bloemfontein this weekend before returning home for the finale.

The All Blacks gather in Auckland on Sunday and cross the Tasman that day.

New Zealand squad: Mils Muliaina, Israel Dagg, Cory Jane, Joe Rokocoko, Rene Ranger, Conrad Smith, Ma'a Nonu, Benson Stanley, Aaron Cruden, Colin Slade, Jimmy Cowan, Piri Weepu, Kieran Read, Richie McCaw (capt), Jerome Kaino, Victor Vito, Brad Thorn, Tom Donnelly, Sam Whitelock, Anthony Boric, Owen Franks, Ben Franks, John Afoa, Tony Woodcock, Keven Mealamu, Corey Flynn

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