It will occupy 2500ha of land currently managed by the Conservation Department (DoC) and immediately west of the Makatote Viaduct on SH49, between Ohakune and National Park.
The trust is asking for the central 200ha to be returned to the iwi in treaty settlement, and for the surrounding 2300ha to be managed by them.
The central 200ha would have a predator-proof fence and predators would be eliminated, Hirini said. In the surrounding 2300ha "halo", predators would be intensively trapped.
Bush there has been logged, and is now in its second generation. The land is reasonably flat, with historic gorges. The Makatote and Manganui o te Ao rivers and the Waimarino Stream run through it - all important to the iwi.
The project has many supporters. Te Puni Kōkiri (the Ministry for Maori Development) paid for its feasibility study. Horizons Regional Council's Accelerate25 economic development group, Ngā Tāngata Tiaki o Whanganui Trust, Ruapehu District Council and Forest and Bird's Wellington and Whanganui branches helped pay for its business study.
Minister for Treaty of Waitangi Negotiations Andrew Little and Conservation Minister Eugenie Sage both visited the site last year. They met with Uenuku Charitable Trust again on March 17, to consider further support.
Horizons Regional Council's wishlist for post-Covid-19 spending includes $7.2 million for stage one of the sanctuary, putting up the predator-proof fence and eradicating predators inside it.
Stage two would be building a visitor centre.