South Africa made Kane Williamson their number one target as the battling New Zealander ensured his side prospered despite a crippling injury to Ross Taylor on day two of the first Test Thursday.

Williamson led a charmed life at the crease, surviving three edges and a run-out attempt to be 78 not out at stumps with New Zealand 177 for three, 131 runs behind South Africa's first innings total of 308 in Dunedin.

While New Zealand were sweating on the fitness of senior batsman Taylor, who was on eight when he limped off with a calf injury, South African bowling coach Charl Langeveldt said Williamson's wicket was their chief concern.

"We have to try and contain Kane Williamson, definitely he's the key. I'm not sure if Ross Taylor is going to come back," Langeveldt said while conceding Williamson was winning the battle with South Africa's bowling spearhead Vernon Philander.

"I think Kane's on top at the moment but Vernon's a strong character and he will come back."

New Zealand's chief destroyer Trent Boult, with four for 64 in unhelpful bowling conditions, said they would not know until Friday if Taylor could resume playing, but the prospects were not good.

"It's a shame to see him limp off like that. He's big player for us," Boult said.

"He's disappointed as we could all understand but the way he walked off it doesn't look too good."

Taylor was injured running a single during a fiery spell by Morne Morkel, who two balls earlier had hit him on the head.

In his first Test following in a year after a long-injury lay off, Morkel sent down a lively 10 overs for 26 and showed no sign of discomfort.

New Zealand wrapped up the South African innings five overs after lunch, with the last six wickets falling for only 56 runs.

It was a rapid end to an innings where the wicket offered little for the bowlers and Dean Elgar, with his 140, had the tourists well placed at 252 for four.

South Africa removed Tom Latham early, caught behind off Vern Philander for 10, before Williamson and Jeet Raval sparked the innings with a 102-run stand before Raval went for 52.

Streaky Williamson

Williamson survived four close calls during his knock. Keshav Maharaj found the edge when he was on 10, and again on 40, but on both occasions the ball fell fractionally short of Hashim Amla at first slip.

On 72, Williamson was sent back by Henry Nicholls and he made his ground by the slimmest of margins. Four runs later an edge off Philander failed to carry to the slip cordon.

The Maharaj-Amla partnership made no mistake when removing Nicholls for 12, with Amla diving to his left to take a sharp one-handed catch bringing nightwatchman Jeetan Patel to the crease and he was on nine at stumps.

South Africa resumed day two on 229 for four and added a cautious 23 in 12 overs before Neil Wagner claimed the crucial wicket of Dean Elgar to end his 104-run partnership with Temba Bavuma.

It was the beginning of the end for South Africa as Quinton de Kock fell for 10 to his nemesis Patel, dismissed by the off-spinner for the third time in as many innings on this tour.

Patel also bowled Kagiso Rabada while Trent Boult claimed Bavuma for 64, Maharaj for five and finished the innings bowling Philander for 21.

Boult was the sharpest of the New Zealand bowlers with four for 64, while Wagner took three for 88 and Patel finished with 2-85.