All Blacks star Barrett ready to put neck on line to tame Pumas

All Blacks playmaker Beauden Barrett said on Tuesday that he is fit again after a neck injury and ready to help tame Argentina in Saturday's second Test.

A knock to his neck in training ruled Barrett out of Saturday's shock defeat to Argentina in Christchurch, three weeks after he landed on it following a mid-air collision during a loss to South Africa in Mbombela.

New Zealand have lost three consecutive home Tests for the first time in their history and Barrett can boost their backline when they face the Pumas in Hamilton.

"I'm feeling really good. A few more shoulder-on tackles and I'd say I'm just about ready to go," Barrett told reporters.

The 31-year-old, who has played 106 Tests, admitted that two heavy blows to the neck in the space of a few weeks was of obvious concern.

"It all adds up, it is another knock. You try to treat everything in isolation, maybe it had a compounding effect," he said.

"But I have been feeling pretty good this week, just working on rehabbing it."

Barrett has been strengthening his neck to reduce the impact of injuries.

"I've realised that I've got to get a neck like a frontrower to be able to handle these knocks," he joked, "so I've been working hard on it in the gym."

New Zealand were punished for ill-discipline in Christchurch by the boot of Argentina winger Emiliano Boffelli, who landed six penalties.

Argentina won 25-18 for a historic first victory in New Zealand and Barrett said conceding so many penalties was "not good enough and we can't let ourselves down, we need to tidy that up".

The All Blacks have dropped back down to their lowest world ranking of fifth since losing four of their six games so far this season.

"We're frustrated, but we're clear in what needs to be worked on," said Barrett.