The country's first urban growth partnership will see co-ordinated development between Auckland and Hamilton, including working together on transport links.
The Hamilton-Auckland Corridor initiative was signed off on Thursday by Government ministers, local mayors and mana whenua.
The Future-Proof initiative will see the Waikato, Waipa, Matamata-Piako and Hamilton councils work with the Waikato Regional Council, and Auckland City Council, together with the Government and local iwi to improve the way the area will grow.
The New Zealand Transport Agency and Waikato District Health Board were also represented.
The parties will now work together on issues including housing and transport as well as walking and cycling trails and a rail service.