Ngāti Apa ki Te Rā Tō invaded and settled at Te Taitapu and Te Tai Poutini in 1800 under leaders Te Āhuru and Te Ao. Ngāti Apa ki Te Rā Tō defeated Ngāti Tūmatakōkiri at the same time Ngāi Tahu, under Tūhuru, was attacking them, however, settlement was acquired more through intermarriage with Ngāti Wairangi, Ngāi Tahu and Ngāti Tūmatakōkiri than through conflict.
Ngāti Apa survived the turbulent musket wars of the 1830s and had established a pā at Kawatiri in the 1840s. It was here that Government surveyor Brunner would meet his guide Kehu Teina Mahuika.
In 1853, the Crown purchased what they thought was a large part of the Te Waipounamu, the South Island, unbeknownst to its iwi occupants. The Crown soon learnt that the local iwi did not accept their lands had been sold without their consent, negotiation, or payment.
In 1859, James Mackay was instructed by the government to purchase the land on the West Coast of the South Island. He left Nelson with Pūaha Te Rangi of Ngāti Apa ki Te Rā Tō and journeyed to Māwhera Pā (Greymouth).
After detailed negotiations, the Arahura Deed was signed by leading Tai Poutini chiefs, incuding Pūaha te Rangi, at Māwhera on May 21, 1860. This deal saw the chiefs surrender their customary title to nearly 3 million hectares in return for £300 and 10,224 acres (4138 hectares) in reserves. Of this, 3500 acres were reserved as an endowment “for religious, social and moral purposes” while the other 6724 acres were for the use of Ngati Apa ki Te Rā Tō and Ngai Tahu.
Ngāti Apa ki te Rā Tō grievances from the Arahura Purchase would be later ve acknowledged in an apology given by the Crown on October 29, 2011 when Ngāti Apa Ki Te Rā Tō representatives at Omaka Marae in Blenheim signed a Deed of Settlement with the Government.
This came into legislation in 2014.