Aredwood:
High house prices meaning average household size will be larger.
According to the 2013 census, the average household size across NZ was 2.7 people. In Auckland it was 3.0, despite the proliferation of small apartments, units, etc.
Porirua also has an average household size of 3.0. The lowest was Thames-Coromandel, with an average size of 2.2.