Two relevant Articles from Declaration on Rights of Indigenous Peoples

Article 18
Indigenous peoples have the right to participate in decision-making in matters which would affect their rights, through representatives chosen by themselves in accordance with their own procedures, as well as to maintain and develop their own indigenous decision-making institutions.

Article 19
States shall consult and cooperate in good faith with the indigenous peoples concerned through their own representative institutions in order to obtain their free, prior and informed consent before adopting and implementing legislative or administrative measures that may affect them.

The Human Rights Council adopted the Declaration on 29 June 2006

Link to full text of Resolution and text of Declaration at
http://www.ohchr.org/english/issues/indigenous/groups/groups-02.htm