The Whakatōhea Māori Trust Board is being investigated at the request of Māori Development Minister Nanaia Mahuta, who had received a range of complaints.
Michael Heron QC will lead the investigation into the governance and management of the trust and into the 2017 triennial elections of the board.
"In my capacity as Minister for Māori Development I have received a range of complaints and requests from a number of beneficiaries for an investigation into the Board," Minister Mahuta said.
"I am committed to having this investigation happen in a timely and efficient manner so that the people of Te Whakatōhea can find a resolution and are able to progress with their aspirations for the future," she said.
Mr Heron will report back to the minister in August, at which time Mahuta can assess the options.
The Whakatōhea Māori Trust Board was formed in 1952 and administers its assets for member benefits, including the promotion of health, social and economic welfare as well as education and vocational training.