On the same $90,000 gross, a worker takes home roughly R 20 118 more per year in South Africa than in New Zealand. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. New Zealand has very high rent pressure, while South Africa has moderate rent pressure. That means part of the higher take-home in South Africa can be absorbed by rent if you land in a major city.
Healthcare and pensions go in the opposite direction. New Zealand runs a universal healthcare model — Universal public healthcare; supplementary cover is common. South Africa uses a mixed model — Public system is strained; most professionals pay for medical aid. The country with lower take-home often shifts costs that the other country leaves to your private budget.
Net-of-everything, a relocation decision should weigh strong public welfare in New Zealand against basic public welfare in South Africa, plus differences in pension capture, social safety nets, and city-level cost of living.