Labour MP Nanaia Mahuta will be the lead negotiator for the Treaty of Waitangi claim of King Country iwi Ngāti Maniapoto.
The Maniapoto claim is one of two outstanding claims in the Tainui waka area.
The MP for Hauraki-Waikato has whakapapa connections to the iwi, and said she was honoured to be selected to lead the group of three negotiators but knew there was a lot of work to do.
The other two negotiators are Peter Douglas and Mook Hohneck.
Ms Mahuta said it would not affect her current job and she had already spoken to the Labour Party leadership.
"There are numerous way in which MPs have managed a whole number of duties. I've had a conversation with our leader, Andrew Little, and Annette King about this, and they are supportive and confident I'm able to achieve that to the best of my ability."
She has stood down as Labour's Spokesperson for Treaty of Waitangi Negotiations to avoid any conflict of interest.
Ms Mahuta did not think it would affect her election chances next year, as she believed she would be able to manage both roles.
"People know that I have always been committed to the treaty settlement process, I've sat on the Māori Affairs Select Committee and over that time sat and deliberated on a number of treaty settlements.
"I will ensure I'm able to achieve a good outcome for Maniapoto and also represent my electorate on the issues that are important to them."