New Zealand's largest city has declared a state of emergency after torrential rain prompted widespread flooding and evacuations. The downpour in Auckland on Friday shifted houses, stalled traffic and cut power to homes and businesses. The New Zealand Herald reported that a body had been found in Wairau Valley on Auckland's north shore. An Elton John concert, expected to be attended by 40,000 fans, was cancelled minutes before it was due to start. Footage online showed people trapped in waist-deep floodwater and rescuers carrying out evacuations on kayaks. Other pictures showed grocery items floating down the aisles of several flooded supermarkets. "Infrastructure and emergency services alike have been overwhelmed by the impacts of the storm," said Auckland Mayor Wayne Brown.