Analysis: Burning less coal to make electricity helped New Zealand achieve its biggest official annual drop in planet-heating gases since records started in 1990.

The same week those figures came out, Resources Minister Shane Jones told Morning Report New Zealand should develop more of its own coal, rather than importing "dirty" coal from Indonesia.

Jones earlier told Parliament that opposition MPs turned a blind eye while New Zealand imported Indonesian coal "every month, to keep the lights on."

While it's true Genesis Energy - owner of the country's only coal-fired station - burns coal to run its Huntly generators, it last year reported that its last shipment of coal had arrived in July 2022.

Government figures show New Zealand was a net exporter of coal every year since records began, except 2021 - a dry year for hydro, coupled with an unexpected shortage on Genesis' gas field.

That was the year Huntly used record amounts of imported Indonesian coal, pushing up the climate impact of the whole country.