All Black coach Steve Hansen says his squad for the away leg of the Rugby Championship is unlikely to include any surprise call-ups.

Hansen said his role as All Black boss was to show faith in his squad and nurture his fringe players rather than scout up-and-coming talent in provincial competitions.  

"The reality is the players that we are keen on, we keep an eye on," Hansen told New Zealand's LiveSPORT radio.

"The ITM Cup rugby is all about guys getting themselves into the franchise teams from there ... that's the pathway.

"We have used players from there for end-of-year tours before and found what we were seeing at ITM Cup wasn't replicated at our level because the step is just too great.

"So we have taken the attitude that yeah, we'll keep an eye on the fringe players that might come into the team but the other guys are really working their way into franchise sides.

"Cleary we are flexible enough that if someone really stood up and was so outstanding that you could not pick them, we'd look at that player as well."

The All Blacks travel to Argentina to face the Pumas in La Plata on 30 September before they head to South Africa to square off against the Springboks in Soweto a week later.

Hansen’s major selection poser revolves around the injured Dan Carter, whose niggling calf injury means he will have to choose between a third flyhalf in Beauden Barrett and a fifth prop, with the New Zealand coach seemingly leaning towards the former.

Hansen said medical reports showed that Carter should be ready for the Test against the Pumas.

"But we have the option to take three five-eighths if we need to, just to give him a bit more time," he explained.

Hansen went on to defend the selection of veteran scrumhalf Piri Weepu, saying he brings a different dimension to the side than exciting youngster Aaron Smith.

"We saw in Wellington why he is the right fit," Hansen said of Weepu.

"When the game suits his style there's none better.

"He's not the same type of player as Aaron Smith at all. Aaron is nippy and carries the ball whereas Weepu is always looking to organise and get things going off slower ball.

"The two contrasts are great for us when we are in those [differing] games."