Puhi-o-Aotea Rātahi was the third president of the Rātana church. She was born Ērina Wiremu Rātana, probably in 1898 or 1899, at Ōrākeinui, which in later years became the Rātana pā settlement. Her father, Wiremu Rātana, had connections to Ngāti Apa, Ngāti Raukawa and Ngā Wairiki. Her mother, Ihipera Kōria Ērina, was a Methodist of Ngāti Hine descent. Both parents were descendants of the Taranaki tribes Ngā Rauru and Ngāti Ruanui. Her paternal grandfather was the Ngāti Apa and Ngāti Raukawa chief Ngāhina Rātana. Little is known of Ērina's early life. When she was 19 she married Panau te Mīhaia Tāmati, of Rangitāne descent, at Parewanui. They lived at Rangiotū.
The origins of the movement which, in 1925, was to become the Rātana church, lay in the spiritual experiences of Ērina’s elder brother, Tahupōtiki Wiremu Rātana, in 1918. Ērina supported her brother’s work, and from the 1920s at times travelled about the country with Rātana and his attendants, spreading their message of spiritual enlightenment to the Māori people. Puhi-o-Aotea was the spiritual name given to her by her brother.
Panau Tāmati died in 1927, leaving her with four young children; one child had died two years earlier. On 23 January 1940, at Wanganui, she married Ēpiha Rātahi, a staunch follower of the Rātana faith; they had a daughter and also raised a grandson.
Puhi-o-Aotea Rātahi remained active in the movement after her brother’s death in 1939. In 1941 she unveiled and blessed the cornerstone of the refurbished Rātana temple. She succeeded her nephew, Matiu Rātana, as president of the movement in 1950. In 1955 she approved a reformulation of the church’s doctrines, which no longer mentioned the Māngai (T. W. Rātana) in the same phrase as the Holy Trinity. It was a time when Māori were coming to terms with the modern era of technology and urbanisation, and her work for the church was linked to her close interest in the welfare of Māori. She supported the advancement of the mōrehu, as Rātana’s followers were known, and Māori as a whole, through education, becoming a life member of the Māori Education Foundation in August 1961. Despite controversy aroused among mōrehu, Rātahi endorsed a book written about Rātana by J. McLeod Henderson in 1963. She acknowledged that in the past it had been church policy ‘not to publicise its teachings’, which had been orally given in the Māori language. However, her intention was to provide a means whereby the younger generation, especially mōrehu, might gain a ‘better understanding of the wonderful power and achievement of our Founder’.
Rātahi travelled about the country to support and encourage Rātana followers. In 1959 she was the patron of the reconstruction committee for Te Ōmeka, the settlement that Rātana established at Te Poi, near Matamata. In 1965 she led the first national tour made by a president of the church since the time of Rātana himself, and led a pilgrimage to Te Rere-o-Kapuni, the sacred stream of Mt Taranaki where Rātana had heard prophetic voices.
Puhi-o-Aotea Rātahi died suddenly at Rātana pā on 17 April 1966. Her tangihanga lasted for a week, during which thousands of mourners, including mōrehu and dignitaries, paid tribute. She was buried at the Piki-te-Ora cemetery at Rātana pā. In 1969 a trophy commemorating her was presented to the Rātana youth movement.