Iwi leader Mike Smith has won the right to sue seven big emitters for their role in causing climate change, in a Supreme Court ruling delivered Wednesday morning.

The climate activist, of Ngāpuhi and Ngāti Kahu, says companies including Fonterra, Z Energy and Genesis Energy have a legal duty to him and others in the community to rein in their greenhouse gases.

RNZ Climate Change correspondent Eloise Gibson spoke to Ben Strang.