The Charter of 1840 specified that the three principal islands of New Zealand were to be known respectively as New Ulster, New Munster, and New Leinster. Under its authority, and in accordance with his instructions, Hobson, who now became Governor, summoned an Executive Council to advise and assist him. This Council comprised the Colonial Secretary, the Attorney-General, and the Treasurer. The Charter and Instructions also authorised Hobson to constitute a Legislative Council of seven persons – the Governor himself, the members of the Executive Council, and three nominated Justices of the Peace – to make laws and ordinances “for the peace, order, and good government” of the colony. Neither Council met at all frequently during the governorships of Hobson and his successors, Lieutenant Willoughby Shortland (administrator), Robert FitzRoy and Sir George Grey. Throughout the Crown colony period each Governor held in the name of the Crown complete control over the executive and legislative functions of government.

Naturally enough, there was a growing agitation from the settlers for representative government. This was particularly the case in Wellington which, as a New Zealand Company settlement, had active supporters in London. Auckland, then the capital, was less interested. Eventually, pressure led to the enactment in 1846 in London of a most intricate constitution. It provided for a three-tiered system of representative government. Municipal corporations were to be created with the powers of English boroughs. Two or more provinces were to be established with assemblies which would include a Governor, a nominated Legislative Council, and a House of Representatives elected by the mayor and councillors of the municipalities in the province. Then there was to be a General Assembly for the whole colony consisting of a Governor-in-Chief, a nominated Legislative Council, and a House of Representatives appointed by the houses of the provinces from their own members.

This constitution was ill-conceived in its complexity; and Grey, the Governor, was able to argue that it would place the Maori majority under the political control of the settlers and so prejudice his efforts to pacify the Maoris. There was also the suspicion that Grey was unwilling to relinquish his own authority. He was able to persuade the British Government that its action was precipitate; and in 1848 (just before Grey divided the colony into two provinces, New Ulster and New Munster) the Imperial Parliament passed a Suspending Act under which those parts of the 1846 Constitution dealing with establishment of provincial assemblies and the General Assembly were not to come into force for another five years. The Charter provisions relating to the Legislative Council for the whole colony were revived, with modifications; and the Governor was authorised to establish Legislative Councils in each of the provinces.

Settler pressure for representative institutions and criticism of Grey intensified, and for the next four years the Governor pursued an erratic course which gave little satisfaction to the settlers. Early in 1848 he had appointed Major-General G. D. Pitt (he was followed by Lieutenant-Colonel R. H. Wynyard) as Lieutenant-Governor of New Ulster, and Edward J. Eyre as Lieutenant-Governor of New Munster. Each had associated with him an Executive Council. Later in the same year Grey, through an Ordinance of the General Legislative Council, established nominated Legislative Councils in each province. The Provincial Council of New Ulster was never summoned. In 1851, under the authority of the 1846 Act, Grey made the town of Auckland a municipality, but this step did not relieve the pressure for a Legislative Council which would be representative of the whole province.

The Provincial Council of New Munster had only one legislative session – in 1849 – before it succumbed to the virulent attacks of the Wellington settlers. Grey, sensible to the pressures, inspired an ordinance of the General Legislative Council under which new Legislative Councils would be established in each province with two-thirds of their members elected on a generous franchise. Grey, however, proceeded to implement the ordinance with such deliberation that neither Council met before advice was received that the Parliament at Westminster had passed the New Zealand Constitution Act of 1852.