When the 7.1 magnitude Canterbury earthquake struck at 4.34am on Saturday, the nation's power consumption dipped by 6 percent.
Scientists at Waikato University have been monitoring characteristics of the electricity grid and PhD student Paul Monigatti said at the exact moment the quake struck, the graph showed a massive spike.
"It's very, very clear, the sudden impact that the quake had on the national grid," Mr Monigatti said.
"The aftershocks are also impacting, but to a lesser extent."
NZPA