Play is set to resume at 6.45pm, with both teams playing 43 overs, after rain stopped play at Eden Park with South Africa on 216 for three after 38 overs.
The covers came off a short time ago.
After an hour long delay, overs have been reduced with Duckworth-Lewis coming into play - possibly calculating a target for New Zealand.
The ICC conditions and rules for the tournament states:
12.1 Law 12.1 e) "Every effort will be made to complete the match on the scheduled day with any necessary reduction in overs taking place and only if the minimum number of overs necessary to constitute a match cannot be bowled on the scheduled day will the match be completed on the reserve day."