New Zealand have secured the Rugby Championship for the third straight year courtesy of a bonus-point win against Argentina in La Plata.

Steve Hansen's men started well and scored two tries in the opening 25 minutes through Ben Smith and Israel Dagg to give the away side a comfortable platform.

Beauden Barrett also looked assured with the boot in the absence of the suspended Aaron Cruden, adding two penalties to the New Zealand tally.

With three points on the board, Nicolas Sanchez kicked another penalty just before half time to give the Pumas hope of overhauling a 20-6 deficit.

The All Blacks almost added a third try within a minute of the restart after Richie McCaw's line break helped set up Malakai Fekitoa, but the centre knocked on with the try line approaching.

Julian Savea thought he had scored midway through the second half when he was to quickest to react to Barrett's chip over the Pumas' defence, but replays showed the winger had strayed offside prior to touching down.

However, the prolific winger wouldn't be denied his 27th try in 27 tests as he went over two minutes later.

As the game reached the last quarter, Argentina's best chance of a try appeared to be through using the power of their forward line, but New Zealand's defence was resolute.

In the 67th minute, replacement TJ Perenara added the important fourth try following good work from Dagg and Jerome Kaino. With the bonus point, the All Blacks wrapped up the title as South Africa cannot catch them in the Championship table.

The Pumas earned a late consolation try when Horacio Agulla finally breached the visitors' try line.

New Zealand round off their Rugby Championship campaign with a trip to Johannesburg to face the Springboks next Saturday.