The West coast is sometimes called Te Tai Poutini. This is because in Maori legend a taniwha called poutini resided there.
Pounamu (Greenstone) was apparently made by the taniwha Poutini. He stole a lady called Waitaiki and turned her to greenstone. This happened up the Arahura river. Waitaiki's husband chased Poutini down.
Stewart island is considered the anchor of te waka o maui, the south island. It is called Te Punga o Te Waka a Maui, as in the anchor of the waka.