There are many different tribal traditions about the origins of pounamu. The following is adapted from a version given by Tipene O’Regan of the Ngāi Tahu tribe.
Poutini was a taniwha or guardian of pounamu. He feared another taniwha named Whaitipū, the guardian of Hinehōaka, who was the goddess of sandstone. Traditionally, sandstone knives were used to cut pounamu.
Once, Poutini was being pursued in the sea by Whaitipū and took refuge in a bay at Tūhua (Mayor Island, in the Bay of Plenty). There, Poutini observed a beautiful woman named Waitaiki coming down to the water to bathe. Enthralled by her beauty, he captured her and swam towards the mainland.
When Tamaāhua, Waitaiki’s husband, discovered that his wife was missing, he used karakia (incantations) and divination with a small, dart-like spear to find her. He threw the spear, which pointed towards the location of Poutini.
Tamaāhua chased Poutini through the North Island and down to the South Island, eventually finding him at the Arahura River. Fearing capture, but refusing to give Waitaiki up, Poutini turned her into his own essence – pounamu – and laid her in the river bed at the junction of the Arahura and a nearby stream. That stream became known as Waitaiki, and ever since it has been a significant source of pounamu, as is the Arahura River. Tamaāhua did not see Poutini, who slipped past him, and on finding his wife turned to īnanga (a type of pounamu) he grieved for her and then returned home.