What is migration?
Migration is about people changing location. It is the most volatile component of population change. It has the potential to have a significant effect on population composition at both the national and sub-national levels.
Although migration flows are volatile, with short-term periods of relatively large net inflow or outflow, New Zealand has achieved only small net gains from migration over the longer term. The majority of growth over the last quarter century has come from natural increase.
International travel and migration is about people arriving in and leaving the country.
Internal migration is about people moving between locations within the country.
The two types of migration are linked in many ways. The intensity of the impact of migration depends in part on whether people leaving have different demographic (and other) profiles than those who arrive.
Differences between international and internal migration
A key difference between international and internal migration in New Zealand is that administrative constraints apply to international migration. It is to a large degree controlled directly by policy due to the need to police cross-border travel. People who are not New Zealand citizens or permanent residents are also subject to immigration legislation. Similarly, the inflows and outflows of New Zealand citizens and permanent residents may be modified by policy changes of destination countries.
Meanwhile, internal migration is driven almost entirely by social and economic factors which have implications for regional sustainability and planning.