Damian McKenzie made his All Blacks debut at fullback but could be a backup option at halfback should injuries happen.

The All Blacks won't replace Aaron Smith in South Africa, instead calling on Highlanders first five-eighth Lima Sopoaga and Chiefs utility Damian McKenzie to provide cover for their two remaining halfbacks.

Smith gave an emotional apology at the All Blacks hotel for being seen to enter a disabled toilet with a women at Christchurch Airport while in team kit. He was then expected to begin his long-haul journey home on Thursday (Friday NZ Time) following his one-match suspension, issued by the playing leadership group.

Hurricanes halfback TJ Perenara will start for a second week, and Tawera Kerr-Barlow offer support from the bench against the Springboks.

ANDREW CORNAGA/PHOTOSPORT First-five Lima Sopoaga is another halfback cover option for TJ Perenara and Tawera Kerr-Barlow, following the departure of Aaron Smith.

Should injuries strike either, All Blacks coach Steve Hansen was happy to use existing players within the squad. Sopoaga could be used from the bench; McKenzie called in before the match.

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Counties Manukau's Augustine Pulu, who is serving a one-match suspension for a dangerous tackle and not available until the day after the test, or Hawke's Bay No 9 Brad Weber would have been in line for a call-up.

But Hansen was content with the cover he already had on tour.

"We're not going to," he said about calling in a replacement player. "We've been training another halfback in the squad. There's two scenarios. If we lose one at training, then we could possibly bring one over really late but if not we would bring Damian in to play there. He trained there this morning when we did our clarity run and he'll get some time in the opposition halfback role this afternoon.

"If we lost both halfbacks, as we've done in the past, like we did with [Colin] Slade a few years ago over here [2014 at Ellis Park] then Lima will go there. We try and plan for most what ifs that occur and usually we get most covered. Halfback is always one - we get our halfbacks to practice throwing the ball in if our hooker is in the bin.

"Halfback is a specialist position so you've got to have someone in your group who can jump in there if you lose both in a game."

Using McKenzie, who made his debut at fullback in Buenos Aires last week, at halfback is not considered a long-term proposition.

"I'd like to see him play 10 before he plays nine. If he gets that part of his job right we might think about playing him at nine. He'd play anywhere that kid. If you put him in at hooker he'd be silly enough to play there."

Losing a world-class player such as Smith is a blow for the All Blacks but, publicly at least, Springboks coach Allister Coetzee was not buying into that.

"No not at all," Coetzee said, when asked if Smith's departure was a positive for the Boks. "TJ has been in excellent form in Super Rugby. He's a good All Black and scrumhalf. I don't think there will be any difference. In fact, when it comes to speed of the game and support lines he runs, he is brilliant. He has got pace and you saw that last week in Argentina - the brilliant try that he finished off. He's a classy scrumhalf too."