Eyre foresaw ongoing problems with Māori and to remedy the situation, he instructed land purchase commissioner Walter Mantell and surveyor Alfred Wills to define the native reserves after the winter. Māori chiefs north of the Waimakariri River disputed that their land had ever been sold and demanded a corridor wide along the Waimakariri all the way to the Southern Alps, plus all the coastal land between the Waimakariri and the Ashley. Mantell granted them a reserve of at Tuahiwi, the pa site at Kaiapoi, and at a pa on the north bank of the Waimakariri. South of that river, reserves set aside were at Taumutu near the outlet of Lake Ellesmere / Te Waihora (), at Arowhenua (south of Temuka; ), on the Temuka River (Te Umu Kaha River; ), at Caroline Bay (later part of Timaru; ), and on the north bank of the Waitaki River (). The work was carried out in August and September 1848 and excluded Banks Peninsula.