All Black Ma'a Nonu is eagerly anticipating a massive midfield duel for himself and centre partner Conrad Smith on Saturday, no matter who the Springboks pick at centre for their Tri-Nations encounter in Bloemfontein.

With Adi Jacobs and Jaque Fourie struggling with injury and Wynand Olivier's call-up as cover, it is unsure which centre pairing will turn out for the Boks on the weekend, but with the options available, it will be a strong combination regardless of who is selected, according to Nonu.

"They are all good players and in midfield they have a bit of a jam with Jaque Fourie, Jean de Villiers and Adi Jacobs, and they are all going well. They are lucky to have the players they have at their level. I'm glad I am not the coach that picks their team," said Nonu from the team's base in Centurion.

Nonu admitted that the All Black back division had struggled to breach the Wallaby defence with any regularity, and he doesn't expect their job to be any easier against the strong Bok backline.

"At the set-piece we got shut down a bit by Australia, and they have a strong backline that likes to rush. I'm sure the South Africans wouldn't like anyone breaking their line. They have a strong defence," said Nonu.

Nonu is relishing the opportunity of testing himself against Jean De Villiers, who he concedes is the world's premier No.12.

"I wouldn't say that I am the world's finest [centre]. He [De Villiers] is at the moment. It is always a challenge playing against world class players like De Villiers.

"I've played against him a few times and it has always been enjoyable, and I'm sure for all of us in New Zealand, and playing for the All Blacks it is always a great challenge. I like to take on a challenge and it is going to be a big one," Nonu quipped.

Nonu also hoped a move away from the cold, evening tests in New Zealand would lift the All Blacks' attacking game. They have scored just seven tries in their first four tests, their dullest start since 1994.

"It's always a bonus to play in the day, especially in South Africa," Nonu said.

"Playing in New Zealand, it's wet and pretty cold so you don't see a lot of flash rugby where the ball goes wide.

"Hopefully on the weekend you'll see a lot of running football.

"There's a bit of a strategy group that pitches in with the coaches and comes up with a game plan that we can work around."