Steve Hansen said New Zealand's hard-fought Rugby Championship win over Argentina gives them "a little bit more money in the bank" having triumphed without so many key men.

Captain Kieran Read, Sam Whitelock, Owen Franks, Joe Moody and Codie Taylor were among the All Blacks to be rested for their opening game of the tournament on Saturday.

The understrength world champions had to dig deep to edge a 20-16 victory over the Pumas, secured courtesy of tries from Ngani Laumape and Brodie Retallick, along with 10 points from the boot of Beauden Barrett.

Head coach Hansen was relieved that his selection gamble paid off ahead of a showdown with South Africa in Wellington next Saturday.

"If you look at the Crusaders not being here [in Buenos Aires] It's a minimum of probably 400 Test caps, but we knew that," Hansen said.

"That's why we talked earlier in the week about risk and reward."

Hansen added: "At times we were rusty, but we did a lot of good things.

"One of the greatest things we did was at the end with all the young fellows on we showed a lot of mental fortitude. So really pleased with that.

"To get away with the win is a little bit more money in the bank."