McCaw is regarded as the best openside flanker in New Zealand history and his absence, after the departure of the equally accomplished Daniel Carter, would be a potentially crippling blow for the All Blacks.
Speculation about McCaw's fitness was fuelled on Wednesday when another openside flanker Matt Todd trained with the All Blacks and on Thursday Zealand assistant coach Steve Hansen pre-empted the expected barrage of questions at a morning news conference when he announced: "Richie McCaw's foot is fine."
"Matt Todd is in Auckland and it just made common sense to have him here," Hansen added. "Now that doesn't mean to say that Richie's foot is any worse than it was, it doesn't mean that Richie is not playing on Sunday.
"It just means that Matt Todd was in Auckland and that we wanted to use him for training as opposition.
"Matt Todd is part of our wider training group and trained with us in Christchurch as did other players down there. We've had wider training group players come in for training at all the venues."
Hansen said McCaw had not trained on the pitch last week and would probably not train again on the pitch this week until Friday.
The 30-year-old loose forward missed two months of this year's Super 15 competition after a screw was inserted in the fifth metatarsal of his right foot. He sat out New Zealand's final group match against Canada after missing the Japan match with a back injury but played against Argentina in last week's quarter-finals.
"I think he played pretty well last week. It was a tough game last week for loose forwards, I thought, because the Pumas were outstanding defensively and got a lot of numbers in the breakdown. It was a tough game and I thought he played well," Hansen said.
"We're very happy where we are with our loose forwards. Our loose forwards have got niggles but I'd suggest the other three sides, they'd all have niggles. That's what tournament rugby is about, the fittest stay the strongest and longest."
The All Blacks will announce their team for Sunday's match against their trans-Tasman rivals Australia on Friday morning and are likely to retain the half-back combination which served them well against Argentina.
In Carter's absence with a groin injury sustained during kicking practice, scrum-half Piri Weepu assumed the kicking duties. Weepu succeeded with seven penalties from as many attempts, failing with a conversion only.
Aaron Cruden, New Zealand's third choice at fly-half, played impressively after Carter's understudy Colin Slade left the field with a groin injury.
Hansen said reserve loose forward Adam Thomson, who was scheduled to have a fitness test on an injured ankle, was the only injury concern.