The South Africa captain Graeme Smith and veteran all-rounder Jacques Kallis both scored centuries and combined for a 200-run partnership as the tourists seized control of the first cricket test in Dunedin.
The pair virtually batted New Zealand out of the match, helping the Proteas to 268 for three at stumps on day three, a second innings lead of 233 runs at the University Oval.
But the Black Caps bowler Doug Bracewell has kept local hopes alive, claiming three wickets for 53 including bowling Smith for 115.
Jacques Rudolph survived an LBW ruling on review and is not out on 13 with Kallis still there on 107.
The Black Caps were dismissed in their first innings for 273 with Trent Boult unbeaten on 33.