His Excellency, the Governor General, the Right Honourable Sir Jerry Mateparae, GNZM, QSO, presented Mr Mihinui with the trophy before an audience of nearly 600 people.
The other two finalists in the competition were Tauhara Moana Trust (Taupo) and Wharepi Whanau Trust (Te Puke).
Ahuwhenua competition management committee chairman Kingi Smiler said the success of Kapenga M highlighted the sophistication of an increasing number of highly successful Maori-owned agribusinesses.
"At the heart of their success is the priority they put on environmental and cultural concerns," he said.
"They know that as the current caretakers of their land, they are responsible for ensuring this precious resource is available to future generations to provide for themselves and their families and to contribute to the wealth and prosperity of the whole country."
Kapenga M Trust has 915 shareholders of Tuhourangi descent and runs a herd of 1020 on its dairy unit, 20km south of Rotorua.
Since 2009, the farm's total milk production has increased steadily from 241,441kg in 2008 to 371,169kg although the herd numbers increased by just nine.
The trust, which won the Ahuwhenua Trophy for sheep and beef farming in 2003, owns a total of 1858 hectares, including a sheep and beef farm and a deer farm.
The trust is currently harvesting 100 hectares of forestry woodlots planted 28 years ago.
Proceeds from the harvest, coupled with last year's record Fonterra payout, encouraged the trust to consolidate its property and grow its holdings to include land with genealogical connections to its current owners.
In 2008, it sold its dairy farm at Mamaku and has bought a 250ha dairy farm adjacent to its Waikite Valley holdings.
The trust also provides education and kaumatua grants and is a foundation investor in the Te Arawa Future Farming Training programme.
The Ahuwhenua Trophy is the premier award for Maori in agriculture, celebrating business excellence in the New Zealand pastoral sector and open to Maori farming properties owned individually or managed by trusts or incorporations.
Each year, it alternates between beef and sheep farms and dairy farms.
This is the fourth year since the competition was revived in 2003 that entrants have competed for the Ahuwhenua Trophy for excellence in Maori dairy farming.
Tangaroa Walker (Ranginui/Pukenga) won the Young Maori Farmer Cadet/Trainee Award.