The English schwa is very common in unstressed syllables. It occurs in the first and third syllables of the word banana. However, the English of New Zealand is distinct because the schwa also occurs in stressed syllables.
The following words are pronounced with the schwa in New Zealand English:
big
fish
hill
pillow
printer
six
skin
trick
swim
window
In other dialects of English, the words have the high front unrounded lax vowel. The same vowel exists in New Zealand English, but not in the words of the list. It exists in words such as friend and when. The schwa is used more extensively in New Zealand English than in other dialects.