'You grow and develop. He's done that' - Hansen

New Zealand boss Steve Hansen is wary of the threat posed by Argentina under the leadership of former Australia forwards coach Mario Ledesma.

Ledesma was appointed the new Pumas boss last month after impressing in his brief first stint as a head coach with Jaguares, but the ex-international hooker previously served on Michael Cheika's staff with the Wallabies.

And after a bright start with Argentina, winning and losing a game apiece against South Africa, Hansen has already identified ways in which Ledesma's experience has helped him to improve the Pumas.

"I think [Ledesma's] time with Australia will have broadened how he thinks about the game," Hansen said. "It's no different to any of us if we get outside our comfort zone, outside of our own national way of playing.

"You grow and develop. He's done that, taken it back to Argentina and got pretty good results so far.

"They like to play it up the middle but they now look like they want to use the backs. Their backs are big and fast, so it is going to be a good contest."

The All Blacks face Argentina in Nelson on Saturday in their latest Rugby Championship fixture.