Tūhoe is backing controversial plans to demolish the historic Āniwaniwa Visitor Centre next to Lake Waikaremoana.
A spokesperson said the $5 million replacement it had helped design marked a new beginning for the iwi.
The Department of Conservation is facing a growing chorus of architects and heritage supporters calling for it to review its decision to destroy what they say is a national treasure.
The Āniwaniwa Visitor Centre was designed by eminent Māori architect John Scott.
Built in 1976, it was condemned as unsafe by DOC and closed in 2008.
Waikaremoana Tribal Authority chair Dana Rurehe said the new building, Te Wharehou o Waikaremoana, was designed to depict who Tūhoe was as a people.
"This is the beginning of the return to the lakeside of nā hapū o Tūhoe".
Te Urewera Board and Te Uru Taumatua chair Tamati Kruger said the new visitor centre would cost DOC $2m and Tūhoe would pay the remaining $3m.
"We are very supportive of DOC's view to remove the building and also for repurposing the native timber in the new build that will be opened on December 23 this year."
Mr Kruger said the iwi co-designed the Wharehou with Tennent Brown Architects.
The new centre incorporated the latest 'green' technology and the architecture was sensitive to its environment, he said, but would also salvage material from the original centre.
Mr Kruger did not dispute the Āniwaniwa Visitor Centre was of architectural value, he said, but that was not the only thing at stake.
"I wouldn't argue against it. I'm not an architect myself, but we acknowledge the heritage value of the old VC [visitors centre] building and all of the accolades that the New Zealand Architects Institute have put on it - that's really not in dispute, what we have to consider is who comes first: Tūhoe interests or architectural interests?"
The Institute of Architects expressed dismay at the decision to demolish a John Scott building.
It said Mr Scott had been a pioneering Māori architect and an outstanding figure in 20th-century New Zealand architecture.
Historic Places Trust president James Blackburne said Mr Scott's ability to mix European and Māori concepts and weave them into something beautiful was unparalleled.
The Āniwaniwa Visitor Centre was a national taonga and a proper debate in the public realm had not happened. He said DOC had been planning its demolition behind closed doors.
"As a community we need to have that discussion, ultimately the building belongs to the nation. At the moment as a nation we're not having the opportunity to have that discussion."
Consultant engineer Peter Smith assessed the Āniwaniwa Visitor Centre building in 2011 on behalf of the Gisborne Hawke's Bay Branch of New Zealand Architects.
He said it was a wonderful building that DOC could save if it wanted to.
"The building had some deterioration to its structural elements and there were some areas of the building which had a strength less than what the code requires in respect of an earthquake-prone building at the time.
"However we were satisfied that the building as a whole was not an earthquake-prone building and we're quite confident it would still meet that requirement."
Senior lecturer at the School of Architecture and Planning at the University of Auckland Bill McKay said the visitor centre could be kept and Tūhoe buildings built alongside.
"There was enough scope around that particular building that they could've worked with it in a way that built on what Māori architects had done in the past."
In a statement, DOC said the new Wharehou would re-establish Tūhoe on the shores of the lake and would include visitor facilities.
It said the old Āniwaniwa Visitor Centre had always been difficult to maintain due to weathertightness issues and earthquake susceptibility.