Labour's Maori Affairs spokesperson Parekura Horomia says Sir Tumu te Heuheu, is stepping down from key Ngati Tuwharetoa roles to reduce his workload - but will remain the tribe's paramount chief.
Sir Tumu recently lost his younger brother - Timoti te Heuheu was 68.
Mr Horomia indicated to Te Manu Korihi on Wednesday that the decision wasn't spontaneous. He said Sir Tumu has held a heavy work load over the years.
Mr Horomia says he's worked towards a succession plan and has chosen to step away from key executive roles in the iwi, but will continue in his role as paramount chief.
In May, Sir Tumu appeared before Parliament's Finance and Expenditure Select Committee, which was hearing submissions in relation to the partial sale of State assets.
Sir Tumu told MPs his iwi would consider legal action if the Government does not consider the tribe's interests in water - before shares are sold.
He is also a member of the Iwi Leaders Group, which talks to the Crown about freshwater issues.