Hakiwai was the fourth child born to a farming family at Manutuke. As a baby she became the tamaiti whangai of Tamati Pewhairangi of Tokomaru Bay, where she stayed until she was sent to a boarding school for Maori girls at the age of 14.
In 1913 she married Mare Nepe Apatu in an arranged marriage; they had three children. After her husband died in 1920 she became a cook for a shearing gang until she remarried in 1934; her second husband was an Anglican priest and also a widow, but he died after only a year, leaving her with a baby son. To support her family she now became a canning factory worker and farm laborer.
Although a humble woman with few resources, she became an important woman of mana among the Maori of the Hastings region. Her home was open to all; she was a founder of the Te Awapuni Women's Institute, of the Maori Women's Welfare League and of the Maori Education Foundation.