It still shows the remnants of the heavily palisaded Otumoetai Pa which has been deserted since 1864.
The blessing and official opening were carried out under the impressive gateway carvings by Damien Kohu and Whare Thompson.
The central figure is Kinonui, a 16th century ancestor who held mana whenua in Tauranga, 18 generations removed from Mr Kohu. Flanking Kinonui are his two sons, Kinomoerua and Kinotaraia. Carved on top of Kinonui's head is Rongotane, the supreme being and greatest son of the sky father. Under Kinonui is Ranginui.
The other carvings represent the palisades of a fighting pa. Otumoetai held the distinction of never being conquered by enemies, including seeing off Nga Puhi chief Hone Heke.
Mr Kohu said they were really grateful for the foresight of Mr Matheson in making sure the land became a reserve.
The pa site was chosen because it had one of the best food sources in the country in the 1600s, including the biggest pipi beds.
Mr Crosby said the next step in the development of the reserve was to erect interpretation panels that told the story of the pa and the land's subsequent settlement by Europeans.
An important part of the development of the reserve was to to keep the original gate posts of the Matheson family's Fairview Farm, with the Matua Residents' Association funding the construction of a replica gate by the Tauranga Woodcrafters Guild.
Mr Crosby paid tribute to the other key stakeholders in the reserve, Ngai Tamarawaho, the New Zealand Historic Places Trust and the Public Trust representing Mr Matheson's Fairview Trust. Mr Matheson died in January 2011.