Proteas bowler Ngidi out of second NZ Test

South Africa paceman Lungi Ngidi has been ruled out of the second and final Test against New Zealand with a back strain.

The 25-year-old missed the first Test, which saw South Africa thrashed by an innings and 276 runs in Christchurch over the weekend.

"Because he hasn't been able to bowl last week, I don't think his bowling loads are up to the standard of preparing for Test matches," captain Dean Elgar told reporters.

"He hasn't been training with us, he's only been bowling off a short run-up, which has been a bit of a setback for us.

"We know Lungi's been a key figure within our bowling line-up. So it's a bit disappointing that he's in the situation that he's in now."

South Africa went with the four-prong pace attack of Kagiso Rabada, Marco Jansen, Duanne Olivier and Glenton Stuurman in the first Test but the strategy misfired, with New Zealand's batsmen racking up 482 to set a platform for victory.

Stuurman had a torrid debut, conceding 1-124 at more than four runs an over, and could be replaced by two-Test quick Lutho Sipamla or Keshav Maharaj if the Proteas opt for a specialist spinner.

With multiple players out of form, Elgar said selection changes were a "big possibility" while declining to name any.

"I'm sure there are guys who are a little bit low in confidence, especially from a batting point of view," he said of a team that scored just 95 and 111 in the series-opener, their second-worst Test defeat ever.