Brendon McCullum: Jesse Ryder not ready

Batting has been a problem for McCullum's team, who are trailing the three-match one-day international series 2-0 heading into Monday's clash in Hamilton.

Only Luke Ronchi (178 runs) has stepped up for the hosts, and he has the most runs of any player in the series.

Tom Latham (45 runs) is New Zealand's next highest scorer.

It has led to calls for Jesse Ryder to return, with the explosive left-hander smashing 136 off 57 balls for Otago against an Ireland side on Thursday.

But McCullum said Ryder still had work to do after multiple off-field incidents.

"I've already said we won't compromise the environment because we represent our country and there's certain obligations which you need to uphold out of respect to the people who support this team," he told a news conference after his side's 72-run loss in game two on Friday.

"Jesse knows he's got some work to do, he's an undoubted talent and if he can get himself right and he's scoring runs and a vacancy is there and the group's ready for him, I see no reason why he can't come back.

"But until that happens we'd be trying to push something that is not quite ready."

In both games, New Zealand's top order has struggled.

They were 156-9 in the opener before Ronchi made 99 to guide them to 230, while they slumped to 95-7 before a late recovery in the second game.

For South Africa, Hashim Amla (157 runs), AB De Villiers (126), JP Duminy (77) and Faf Du Plessis (75) have contributed.

Vernon Philander and Imran Tahir have both taken a series-leading four wickets, along with New Zealand paceman Trent Boult.

But the batting has been the difference so far and McCullum will be hoping that can begin to change in game three.