Buenos Aires - New Zealand coach Steve Hansen called prop Karl Tu'inukuafe an "unpolished diamond" on Sunday after a 35-17 Rugby Championship title-clinching victory over Argentina in Buenos Aires.

The All Blacks destroyed the Pumas in the scrums - a humiliating experience for a South American nation once outstanding in that aspect of the sport.

Loosehead Tu'inukuafe, hooker Codie Taylor and tighthead Ofa Tu'ungafasi tormented the Argentines, even though neither prop is a first choice.

They started at Estadio Jose Amalfitani as loosehead Joe Moody is injured and tighthead Owen Franks was rested by 2015 Rugby World Cup-winning coach Hansen.

"He could become great," said Hansen of Tu'inukuafe after New Zealand sealed a sixth title in the seven-year southern hemisphere tournament.

"Karl certainly can scrum, can lift in the lineouts, and we are starting to see other parts of his game, too. But Karl will be the first to tell you he is not the finished product.

"You go looking for nice coloured stones and you turn a wee rock over and under it there is a diamond. We just need to polish it and get the full diamond."

Ardie Savea, a late inclusion at number eight in place of ill Luke Whitelock, was another forward to get special praise from Hansen.

"I thought Ardie was outstanding," said the 59-year-old coach who succeeded Graham Henry after hosts New Zealand won the 2011 Rugby World Cup.

"Our scrum was outstanding and he controlled the ball at the back and won us a lot of penalties because of that.

"He did excellent work around the park as well, with and without the ball," the coach said after a match that gave New Zealand a 27th win over Argentina in 28 Tests with one drawn.

"We were better, but you do not go from zero to 100 immediately," said the coach of a triumph that came two weeks after a stunning 36-34 defeat by South Africa in Wellington.

"I thought our kicking was better, maybe not as accurate as we would have liked, but we kicked to the right places at the right times a lot more than we did against the Springboks.

"At times we played some good footy and at other times we did not play that great. But let us credit Argentina, too. They are a difficult side to play against, especially here."

In the final Championship fixtures this Saturday, New Zealand tackle second-place South Africa in Pretoria and third-place Argentina face rock-bottom Australia in Salta.