The Public Service Association says 66 jobs will be lost at Te Puni Kokiri, cutting the workforce down to just under 300.
Leadership at Te Puni Kokiri, the Ministry for Maori Development, have described the restructure as a "recruitment and reassignment process" and say who will stay and who will go will not be known for up to two months.
A document leaked to Radio New Zealand shows the depth of the changes.
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The ministry said it was to focus on a narrower range of mahi, saying that streamling would make a positive difference for iwi, hapu and whanau Maori focusing on five key areas to maximise the impact of its work.
Te Puni Kokiri has confirmed that regional staff were flown to Wellington for the announcement and to be given their letters, as well as staff from Auckland, Christchurch and Dunedin.
Curriculum vitae workshops for staff have bee taking place from 18 August until next month, as well as workshops entitled "Coping with Change". Staff who are to be made redundant will be offered support.
There are a number of new roles with previous ones being cut, such as in the Policy Partnerships Wahanga, where four director and 10 manager roles will be lost.