Some people might be surprised by the statement that New Zealand has much higher birth rates than the countries of North-East Asia.
There is always scope for debate about the fine grain of these population projections, influenced by how birth rates might further change.
In the case of New Zealand, the assumption is that birth rates will remain much as they are now.
Even if there is no net migration to New Zealand, the New Zealand population will increase until the 2040s, at which time new deaths will catch up with new births.
However, as birth rates decline below 2.1 children per woman, they reconfigure, first like a misshapen brick wall and then they go inverted.