The relationship evolved as New Zealand moved toward independence, adopting the Statute of Westminster in 1947, and diversifying its foreign and economic policies.

[1] The two countries remain related through mutual migration, through shared military history, system of government, and head of state, and through language and membership of the Commonwealth (formerly British Empire).

Secret directives had been supplied to Cook for this portion of his expedition, instructing him to search firstly for the fabled Terra Australis and, if unsuccessful, to make instead as extensive an exploration of the New Zealand coast as resources allowed.

The document that Cook was given declared that these missions were intended to further demonstrate Great Britain's maritime prowess, to bring honour to the Crown and to explore new opportunities for trade and navigation.

As part of this process, King William IV recognised and agreed to act as protector for the newly formed state.

Formal British influence gradually diminished, as the power of successive Governors waned with respect to that of the nascent New Zealand Parliament.

Dominion status followed in 1907, providing almost complete independence from the government of Britain and New Zealand separately joined the League of Nations in 1926.

[3] From the anglicisation of the Dutch appellation Nieuw Zeeland onward, historical ties with the United Kingdom have contributed substantially to New Zealand's toponymy.

[citation needed] James Cook's early map combined local Māori place-names with a number of his own coinages.

[12] Historically, some industries, such as dairying, a major economic factor in the former colony, had even more dominant trade links, with 80–100% of all cheese and butter exports going to Britain from around 1890 to 1940.

[18][19] The United Kingdom has completed negotiations to accede to Comprehensive and Progressive Agreement for Trans-Pacific Partnership on 31 March 2023, of which New Zealand is a founding member.

The first interclub rugby union match in New Zealand, in Nelson, took place in 1870 and was inspired by a teacher returning from England with a knowledge of the new game.

Subsequently, separate appointments were made; this distinguished the representation of the British Government in New Zealand from that of the shared monarch, in sympathy with the principles set out under the Balfour declaration thirteen years earlier.

Several New Zealand public bodies have official representatives in Britain and Honorary Consuls are based in the UK constituent countries of Scotland and Northern Ireland.