The All Blacks have won the Rugby Championship after South Africa couldn't chase them down despite beating Argentina in their final game.

The Springboks didn't claim a bonus point in their 38-21 win to finish on 18 points on the table, one point behind the All Blacks.

It is New Zealand's eighth Rugby Championship title since Argentina was added to the new format in 2012. The title was all but confirmed when Ian Foster's men thrashed Australia 40-14 in the second Bledisloe Cup clash at Eden Park last night.

South Africa scored five tries in the 38-21 win over a stubborn Argentina but it wasn't enough to wrestle the title away from New Zealand.

South Africa needed a bonus-point victory and to win by more than 39 points to steal the crown at the very end of the championship, but the Springboks didn't even get their bonus point.

Argentina scored three tries of its own and twice closed the gap to three points at 17-14 and 24-21 in Durban before the Boks got away in the last 10 minutes.

Replacement Kurt-Lee Arendse ran in South Africa's last try after the final hooter but by then the All Blacks were the southern hemisphere champions once again.