Power sharing regimes in resource management, including co-governance and co-management schemes, are now common across New Zealand. These schemes bring together iwi and the Crown to facilitate various environmental objectives. These arrangements often utilise the tenants of tikanga Māori, in particular the concept of kaitiakitanga, and are generally provided for outside of the Resource Management Act 1991. This thesis shows how two iwi, Ngāi Tahu of the South Island, and Ngāi Tūhoe of Te Urewera in the central North Island, are utilising such schemes to promote the interests of their people. It explains that Ngāi Tahu have built up co-governance in a patchwork manner, utilising the provisions of their settlement to build three distinct co-management arrangements in Canterbury. The thesis shows that Ngāi Tahu have yet to gain full co-governance capacity, but may well have a future role at the table in regional Canterbury governance from 2016 onwards. In comparison, Ngāi Tūhoe have been granted a different kind of governance arrangement that arguably goes beyond co-governance. This governance arrangement is based off the fact that legal personality has been granted to Te Urewera, and will allow Ngāi Tūhoe to promote the interests of their people in a unique way. The thesis will show that the face of co-governance is changing, and the future face of such arrangements may well give iwi more control. However, that there are pitfalls associated with such resource management power sharing schemes that must be taken into account when planning for future arrangements.