Economic development is one of the tribe's other main focuses, and buying the Waverley site is part of that.
The decision to buy was made on November 2, and settlement day with the Education Ministry will be January 5. Ms Broughton would not give the price.
Nga Rauru's $31 million treaty settlement happened in 2005, and its fund has grown since.
Waverley High School closed in 2007 and most of the remaining buildings, badly vandalised, were demolished this year.
The sale gives Nga Rauru 5.6ha of flat, bare, fertile land, "a lovely clean canvas for us to start creating from," Ms Broughton said.
The land could be a place to trial crops. Ms Broughton is one of the advisers to the Manawatu-Whanganui Regional Growth Study, which is interested in agribusiness.
"By February next year that project should be releasing some findings on what opportunities exist for this region. We will be well positioned to respond to some of those recommendations."
No final decisions have been made about land use.
"We see having the high school as creating a facility where we can grow. Exactly what we grow into is part of the planning that will come about."
The only building left on the high school site is a rundown three-bedroom house. It's to be renovated and become the tribe's office. Four full-time staff will work from it, and contractors will come and go.
Ms Broughton said staff were looking forward to the move.
"To be back in the Nga Rauru heartland and able to work very closely with Waitotara, Waverley and Patea communities will be very exciting."
Nga Rauru is also beginning a social ecological entrepreneurship programme in January, led by Massey University ecological economist Dr Marjan van den Belt.
The first two days are January 27 and 28, and will intersect with the iwi's fourth annual Waitotara Awa Hikoi at Takirau Marae.
The programme is about creating entrepreneurs who respect the needs of people and the environment, Ms Broughton said.
