From Academic Kids
In New Zealand, it is applied to a person who has emigrated from one of the smaller islands of the Pacific to New Zealand in modern times, or one of their descendants born in New Zealand. While the majority of these people originate from Polynesia, others come from Micronesia and Melanesia. The term is used to distinguish these people from the indigenous New Zealand Maori (who are also Polynesian but arrived in New Zealand many centuries earlier), and from other ethnic groups. A major reason for making the ethnic distinction is that the Pacific People collectively suffer from socio-economic disadvantages and require culturally targeted social and health assistance.
In Australia, it means a person from Pacific Islands as in New Zealand.
In the United States it refers to people from the same locations living in the U.S. except Native Hawaiians. This would not include New Zealanders. For instance U.S. Census category was "Native Hawaiians and Other Pacific Islander"(NHOPI). NHOPI refers to people having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands. It includes people who indicated their race or races as "Native Hawaiian", "Guamanian or Chamorro", "Samoan", or "Other Pacific Islander", or wrote in entries such as Tahitian, Mariana Islander, or Chuukese. Inhabitants of Chinese, Japanese, Philippine, and Indonesian islands are not considered Pacific Islanders and are classified as "Asians" on the U.S. Census.