The company's Community Conservation Challenge, which started on May 14, ended on Wednesday, with all participating regions where Contact is the major retailer, achieving sizeable donations for their electricity savings. The regions used an average 7% less electricity than for the corresponding two months last year.

South Island communities achieved greater savings than their Northern counterparts. The South Island averaged savings of 10%, while the North Island averaged 5%.

"It's been great to see communities around the country band together and make major electricity savings over the course of the community energy conservation challenge. Individuals have played a large role in preventing a power supply shortage this winter," said Contact chief executive Steve Barrett.