Transpower is reminding people to avoid unnecessary power use.

The grid operator is asking consumers to reduce electricity use between 7am and 9am tomorrow.

An unseasonal cold snap and low wind generation means the country is facing a potential supply shortfall.

Executive operations general manager Chantelle Bramley says they're doing their best to avoid power cuts.

"Generators have been making as much generation available as possible, we've been working with lines companies - and industrial customers have also responded." 

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