The ethnic make-up of New Zealand is changing.  The Health Ministry published its annual report on maternity last week and, for the first time, the Asian birth rate in New Zealand climbed ahead of the European rate. Maori and Pacific birth rates still remained by far the highest, propping up the overall New Zealand fertility rate.
The New Zealand Herald infographic below shows the total number of births per 1000 women over time.  It seems to indicate that Asian women are aware that 30 is the age that fertility begins to decline, as births peak sharply just before this age.  The median age for Māori and Pacific women giving birth was five years younger than for Asian and European women. The increase in the Asian birth rate is in part caused by Asian students first coming to New Zealand on temporary student visas then becoming qualified and choosing to have their families here.  It also reflects the changing composition of the Asian population, particularly the increase of Filipino migrants who tend to be of reproductive age and come from a country of higher fertility.
The New Zealand Herald interviewed Eva Chen, a Taiwanese mother who has done more than average to lift the Asian New Zealand birth rate, about why she currrently has four children between 9 and 11 months.  She commented that:

"Most of us just want to have one or two; three will be the maximum they think they can handle. I like to have four because I come from a big family. More kids is fun,".   The 35 year old came to New Zealand in 1997 as a student.  She is now the chief executive of the Wellbeing Charitable Trust Board Chinese Family Service, which helps Chinese immigrants adapt to New Zealand ways of parenting.
The overall New Zealand birth rate remained stable from 2008 to 2012, ranging from 68.6 to 71.1 births per 1000 females of reproductive age.  The total fertility rate has hovered just under replacement rate for most of the last few decades, as shown in the graph below.  As in many countries, such as the United States, cultural change is taking place in New Zealand reflective of birth rates.