British Sovereignty (1788-1842)
In 1788 the colony of New South Wales had been founded. The colony included most of New Zealand except for the southern half of the South Island. In 1825 with Van Diemen's Land (now the Australian island Tasmania) becoming a separate colony, the southern boundary of New South Wales was altered yet again, now included only the northern half of the North Island. However, these boundaries had no real impact as the New South Wales administration had little interest in New Zealand.

In response to complaints about lawless white sailors and adventurers in New Zealand, the British government appointed James Busby as Official Resident in 1832. In 1834 he encouraged Māori chiefs to assert their sovereignty with the signing of the Declaration of Independence in 1835. This was acknowledged by King William IV. Busby was provided with neither legal authority nor military support and was thus ineffective in controlling the European population.

Treaty of Waitangi
In 1839, the New Zealand Company announced its plans to establish colonies in New Zealand. This, and the continuing lawlessness of many of the established settlers, spurred the British to take stronger action. Captain William Hobson was sent to New Zealand to persuade Māori to cede their sovereignty to the British Crown. In reaction to the New Zealand Company's moves, the territory of New South Wales was expanded to include all of New Zealand. Governor of New South Wales George Gipps was appointed Governor over New Zealand. This was the first clear expression of British intent to annex New Zealand.

In 1840, Hobson and about forty Māori chiefs signed the Treaty of Waitangi at Waitangi in the Bay of Islands. A significant number refused to sign or were not asked but, in total, more than five hundred Māori eventually signed.

The Treaty gave Māori sovereignty over their lands and possessions and all of the rights of British citizens. What it gave the British in return depends on the language-version of the Treaty that is referred to. The English version can be said to give the British Crown sovereignty over New Zealand but in the Māori version the Crown receives kawanatanga, which, arguably, is a lesser power. Dispute over the true meaning and the intent of either party remains an issue.

Britain was motivated by the desire to forestall other European powers to facilitate settlement by British subjects and, possibly, to end the lawlessness of European whalers, sealers and traders. Officials and missionaries had their own positions and reputations to protect.

Māori chiefs were motivated by a desire for protection from foreign powers, the establishment of governorship over European settlers and traders in New Zealand, and to allow for wider settlement that would increase trade and prosperity for Māori.

Hobson died in 1842. Robert FitzRoy, the new governor, took some legal steps to recognize Māori custom. However, his successor, George Grey, promoted rapid cultural assimilation and reduction of the land ownership, influence and rights of the Māori.