premise: South Island is rarely referred to as the "mainland" of New Zealand.
hypothesis: The South Island or Te Waipounamu ( Māori ) is the larger of the two major islands of New Zealand , the other being the smaller but more populous North Island . It has a 32 percent larger landmass than the North Island so is sometimes referred to as the `` mainland '' of New Zealand , especially by South Island residents , but only 23 percent of New Zealand 's million inhabitants live there .