The Waikato region led the rest of the country in saving power during Earth Hour - but some areas made no savings at all nor even used slightly more power.
About 130 countries were involved in the event, organised by the World Wildlife Fund, which ran from 8.30pm to 9.30pm NZ time on Saturday.
A Transpower spokesperson, Kieran Devine, says Hamilton saved the most - 2.77%. Palmerston North saved about 1.5% and Christchurch 0.06%.
Napier, the West Coast and Invercargill recorded small increases over the average.
Overall, Mr Devine says, the country saved 2%.