Immigrants average weekly earnings increase by approximately 250 percent when migrating from Tonga to New Zealand. This estimate is less than the difference in either average wages or GDP per capita in each country and is also less than estimates based on research methods that do not account for the self-selection of migrants. However this monetary gain is not necessarily the main motivating factor behind migration decisions, with survey respondents reporting a desire for better public services and to be with family members already in New Zealand as most important factors behind their decision to migrate.
Immigrants face high transactions costs when sending remittances to the Pacific Islands. The most popular methods of sending money, such as Western Union, typically entail transactions costs of 15-20 percent due to both the exchange rate premium charged and the fixed charge (which is proportionately more important for small transfers). These costs are considerably higher than in many other similar-sized remittance markets and are also much higher than some of cheaper methods of sending money from New Zealand to the Pacific.
Migration is found to have complex effects on health. The stature of infants and toddlers increases but offsetting these improvements are increases in body mass and possible obesity among pre-teens. The mental health of adults does not appear to decline in the short run, and migration may even be associated with an improvement, particularly for women.
Changes to the Pacific Access Category in late 2004 appear to have had a positive effect in helping immigrants obtain longer-lasting jobs in New Zealand. In the absence of the job brokering now facilitated by immigration authorities, the extended family in New Zealand play a key role in finding initial job offers for would-be emigrants, which may have limited the accessibility of this migration option.
Despite close links between New Zealand and Tonga (approximately 17 percent of the Tongan population are in New Zealand) potential emigrants do not appear to be well informed about likely wage incomes in New Zealand, and if anything under-estimate these.