Passage: New Zealand was one of the last major landmasses settled by humans. Radiocarbon dating, evidence of deforestation and mitochondrial DNA variability within Māori populations suggest New Zealand was first settled by Eastern Polynesians between 1250 and 1300, concluding a long series of voyages through the southern Pacific islands. Over the centuries that followed, these settlers developed a distinct culture now known as Māori. The population was divided into iwi (tribes) and hapū (subtribes) who would sometimes cooperate, sometimes compete and sometimes fight against each other. At some point a group of Māori migrated to Rēkohu, now known as the Chatham Islands, where they developed their distinct Moriori culture. The Moriori population was all but wiped out between 1835 and 1862, largely because of Taranaki Māori invasion and enslavement in the 1830s, although European diseases also contributed. In 1862 only 101 survived, and the last known full-blooded Moriori died in 1933.

Question: What are the two main tribes of maori?
iwi (tribes) and hapū (subtribes)