Individuals living in or intending to reside in New Zealand who met a good character requirement and were able to pay a £1 fee could apply for naturalisation with the Colonial Secretary's Office.

[27] Growing hostility and anti-Chinese sentiment along with the rise of colonial nationalism led to a concerted movement within the legislature to restrict Chinese immigration.

[30] China, Hong Kong, Mauritius, and the islands of modern Indonesia were declared to be "infected places" under the Public Health Act 1876; ships originating from or stopping in one of these territories, or those that allowed any person or cargo coming from or passing through those areas were subject to strict quarantine on their arrival in New Zealand.

The United Kingdom then ceded administrative control over the Cook Islands and Niue to New Zealand in 1901, and for Tokelau in 1925.

[36] Although Parliament amended nationality law in 1923 and 1928 to allow facilitated naturalisation to Western Samoans wanting to become British subjects,[34] virtually none had taken this option.

Dominions that adopted this Act as part of local legislation were authorised to grant subject status to aliens by imperial naturalisation.

[41] By the end of the First World War, the Dominions had exercised increasing levels of autonomy in managing their own affairs and each by then had developed a distinct national identity.

[42] Women's rights groups throughout the Empire pressured the imperial government during this time to amend nationality regulations that tied a married woman's status to that of her husband.

Combined with the approaching independence of India and Pakistan in 1947, comprehensive nationality law reform was necessary at this point to address ideas that were incompatible with the previous system.

[48] Cook Islanders, Niueans, Tokelauans, and British subjects born in Western Samoa became New Zealand citizens automatically as well.

[54] Commonwealth and Irish women who were married to New Zealand citizens were eligible to acquire citizenship by registration with no further requirements.

[57] All British subjects under the reformed system initially held an automatic right to settle in the United Kingdom and Ireland.

[58][59] Non-white immigration into the UK was systemically discouraged, but strong economic conditions in Britain following the Second World War attracted an unprecedented wave of colonial migration.

[61] Ireland had continued to allow all British subjects free movement despite independence in 1922 as part of the Common Travel Area arrangement, but moved to mirror Britain's restriction in 1962 by limiting this ability only to people born on the islands of Great Britain or Ireland.

[62][59] Britain somewhat relaxed these measures in 1971 for patrials, subjects whose parents or grandparents were born in the United Kingdom,[61] which gave effective preferential treatment to white Commonwealth citizens.

[68] New Zealand made further reforms to its nationality law in 1977 that abolished the preferences that were afforded to citizens from other Commonwealth countries and allowed citizenship to be transferrable by descent to children through mothers as well as fathers.

[69] Commonwealth and Irish citizens remain technically defined in New Zealand law as non-foreign, but there are no benefits provided to either group.

[75] Following a general trend in other common law jurisdictions, New Zealand ended unrestricted birthright citizenship in 2005.

Legislation in the 1920s had allowed Samoans to become British subjects if they chose to but left the status of those who had not completed the formal naturalisation process unclear.

[34] In 1982, the Judicial Committee of the Privy Council ruled that all Western Samoans born between 1928 and 1948 were British subjects and automatically became New Zealand citizens in 1949.

[78] Faced with the prospect of a potential brain drain if large numbers of its people exercised their newfound dual citizenship rights, Western Samoa signed the Protocol to the Treaty of Friendship with New Zealand on 21 August 1982.

This treaty, and the subsequent Citizenship (Western Samoa) Act 1982, effectively nullified the Privy Council ruling.

[81][82] The Cook Islands became a self-governing state in free association with New Zealand in 1965, and Niue gained independence under largely the same terms in 1974.

Peters clarified that a separate Cook Islands passport would involve the territory becoming an independent state, which would have implications for its free association relationship with New Zealand.

[8] New Zealand airspace, its internal and territorial waters, and New Zealand-registered ships and aircraft are treated as part of the Realm for nationality purposes.

[87] Foreigners over the age of 16 may become New Zealand citizens by grant after residing in the Realm for more than five years while possessing indefinite permission to remain.

The only major disadvantage applies to citizens by descent, who cannot pass citizenship to their children born abroad.

[87] These individuals may apply to become citizens by grant after fulfilling the five-year residence and physical presence requirement.

Otherwise, they may apply for their children born overseas to receive citizenship by grant, at the discretion of the Minister of Internal Affairs.