Although for people who would be listening to the two accents for the first time, both New Zealand Accent and Australian Accents might sound very similar, however, there are some differences between the two. One of the major differences in the way some words are pronounced when you listen to people using the two accents.
For instance, most New Zealanders pronounce some words with letter 'H' silently, while the same words will be pronounced by Aussies with letter 'H' coming out very loud. Another difference is that New Zealanders are fond of pronouncing some words by switching the vowel in the word for another vowel.
For instance, a typical New Zealander will pronounce fish as fish. In contrast, this problem is not usually encountered by Aussies when pronouncing the same words. Another difference is that the Australian accent consists of both British and American English, whereas the New Zealand accent is being shaped by some British dialect.