The West Coast Coal Region is the only New Zealand producer of bituminous coal, with significant export markets, and also supplies sub-bituminous coal for the domestic market. Late Cretaceous and Eocene coals are the most important, and there are significant resources of Miocene coal in the eastern part of the region. The Buller and Greymouth bituminous coalfields are the main producers, and contain resources of coal with exceptionally low sulphur and ash contents. Canterbury Coal Region consists of several scattered deposits and coalfields of Late Cretaceous to Eocene and Miocene age. These occur at the base of a transgressive sequence, preserved along the foothills of the Southern Alps.
Known resources are small.
In the Otago Coal Region, Late Cretaceous sub-bituminous and lignite coal measures are present in eastern Otago, with the Kaitangata Coalfield the major deposit. Large lignite deposits of Miocene age are present in Central Otago. These lignites are of Miocene age. 6256 Mt recoverable. Coal at much greater depth within onshore and offshore sedimentary basins is the major source rock for New Zealand's petroleum resource.