Dame Tariana Turia and Turama Hawira have been appointed to the office of Te Pou Tupua.
The pair will act as the human face of Te Awa Tupua, the legal personhood of the Whanganui River, for the next three years.
The river's legal status was established earlier this year by the Te Awa Tupua (Whanganui River Claims Settlement) Act.
Te Pou Tupua - a singular role which represents neither the Crown nor iwi - will speak on behalf of Te Awa Tupua and uphold its four values.
Those are that the river is a source of physical and spiritual sustenance, that it runs from the mountain to the sea and is indivisible, that iwi and hapu have an inalienable relationship with the river and that large streams flow into one another and form one river.