Wallabies inside centre Pat McCabe says a rare win over the All Blacks this weekend will boost confidence but doubts whether it will earn a psychological edge at the World Cup.

McCabe said self-belief was high ahead of Saturday night's Suncorp Stadium showdown where Australia hope to break a 10-year Tri-Nations title drought with a win over New Zealand in the final match.

That's despite a controversial lead-up featuring James O'Connor, suspended for his World Cup squad announcement no-show, and the fuss over a 10-month-old tour incident between O'Connor, Quade Cooper and Kurtley Beale.

"Those guys have had to talk about it a fair bit but personally I haven't given it too much thought," McCabe said on Wednesday. "It hasn't disrupted us."

While McCabe believed a win over the All Blacks would provide a shot in the arm, he doubted whether it would count for much at the World Cup.

"This game is huge. Australia hasn't been in contention to win the Tri-Nations for a long time," McCabe said.

"And the confidence you take out of a game like this if you are the victor that is a great boost coming into the World Cup.

"But I'm not sure it will (mean much) next time we face them.

"But to just have beaten the best in the world ahead of the World Cup would show we are heading in the right direction."

McCabe said the Wallabies backed themselves after the lessons learned from this month's 30-14 Tri Nations loss at Eden Park.

"I think we learned a lot from that game - the physicality we need to bring," he said.

"Especially in that first 20 minutes - we weren't really in the game at all.

"I would like to think we have made those adjustments and it will be a different contest on saturday night."

Due to a backline reshuffle forced by O'Connor's ban, McCabe will be paired with Anthony Fainga'a to take on the formidable midfield duo of Ma'a Nonu and Conrad Smith.

But McCabe backed their budding centre combination after only a handful of Australia A games and several weeks of training together.

"They (Smith, Nonu) are obviously an extremely imposing midfield and one I have never played against as centre," McCabe said.

"If we slow down their breakdown ball they can have less of an influence on the game.

"He (Fainga'a) is a good communicator and enjoys the physical contact.

"Defensively we should be okay and in attack ... he has spent a lot of time with Quade (Cooper at the Reds) so he should feel pretty comfortable on Saturday night."

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