Having been sent in, South Africa - 1-0 up in the three-game series - reached 282 for nine, on the back of a 16th ODI century by opener Hashim Amla, 119, and other strong contributions from Faf du Plessis and captain AB de Villiers.
It was the prolific Amla's first ODI ton against New Zealand in eight innings, and he prospered after two early letoffs.
He edged seamer Tim Southee at catchable height between wicketkeeper Luke Ronchi and first slip on seven. Neither moved for it.
Five runs later he top edged a hook off the same bowler and Dan Vettori at fine leg completely lost the ball. What should have been a regulation catch hit the ground 15m away from the unsighted fielder.
From then on, Amla was in charge, working the ball about the park and at times getting his runs in clumps.
His 100 took 127 balls, then he went on a tear, ripping off four boundaries in four Trent Boult deliveries.
Du Plessis hit an entertaining 67 off 73 balls and de Villiers a brisk 37.
However South Africa's lower order crumbled, losing their last six wickets for 25 - the last five for only three runs - to fall short of what should have been a routine 300-plus total.
On a pitch which played a touch quicker than it had in the opening game of the series last Tuesday, Southee, Trent Boult, Mitchell McClenaghan and Corey Anderson finished with two wickets each, and Jimmy Neesham one each.
