The decline in gas supply has led to production cuts and a 99 percent increase in coal-generated electricity, according to MBIE.

Methanex, New Zealand's biggest energy consumer, has cut back on its methanol production as a result.

Director of Enerlytica, John Kidd, says the system will adjust - but unfortunately this is not a costless exercise.

"Structurally, we're short on energy - full stop. So it's often lost on people that we don't have enough energy in the country to be able to support our demands. So we do rely on international markets anyway."

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