Captain Richie McCaw is confident he will be able to last the full 80 minutes in New Zealand's Tri Nations opener.

The All-Blacks will vie for the Bledisloe Cup against Australia on Saturday.

Aside from appearing for his Christchurch club last weekend, the dynamic openside flanker has not played a top-level game of rugby since he injured his knee in the Super 14 semi-finals back in May.

McCaw's absence took its toll on New Zealand's first three games of the season after the world's number one ranked team bumbled their way through three Test matches against France and Italy.

The All Black selectors have not named a genuine openside flanker as a replacement for McCaw ahead of Saturday's Test so the pressure is on the 28-year-old to last the entire game.

McCaw is confident his body is up to the challenge.

He said: "After watching for a while it's nice to be back into proper training and getting ready for a Test.

"I'm pretty confident that I'll be able to [last 80 minutes]. I guess in the worst case there's Rodney [So'oialo] who's played [at openside flanker] before but hopefully that won't happen.

"I've done three or four good weeks of training and I have had a couple of hit-outs so from that point of view I know where I'm at.

"Although it's hard, the adrenaline and stuff seems to keep you going so I'm pretty confident I'll be fine."

McCaw is expected to provide the leadership and accuracy that has been missing in the All Blacks forward pack this weekend along with number eight So'oialo who also returns from injury and will run out in his 55th Test for New Zealand.

McCaw knows what will be expected from him at Eden Park but said the other senior players in the team need to step up as well if they are to have a successful Tri Nations this year.

"I think all the guys that have been around a while need to get things right and so far this week it's been pretty good," said McCaw.

"Come Saturday we've just got to go out there and perform.

"The guys in key positions, and they're the ones that have been around a while, need to make sure they go out there and perform so from my point of view that's what I'm worried about.

"For me it's not rocket science, it's just about preparing well and getting my own game right."