The turnover of MPs was very high in the 2nd Parliament, with 32 by-elections and a supplementary election being held. This situation was partly the result of a redistribution of boundaries to seven electorates, and the creation of four new electorates – agreed upon in the "Electoral Districts Act, 1858", with the total number of MPs in Parliament rising from 37 to 41, and the number of electorates rising from 24 to 28. The northern portion of the Northern Division electorate was split off and became the electorate of Marsden. The Wairarapa and Hawke's Bay electorate was split into two separate components, and . All the previously unincorporated areas in the lower North Island were divided between Wairarapa, County of Hawke, , and .