Electricity managers will be on alert during the Rugby World Cup to make sure the power supply stays reliable.
Transpower, which operates the national power grid, says a large television audience for big rugby games can put huge pressure on the system.
Senior manager Kieran Devine says Brazil's electricity system came close to failure during a recent football world cup, and he does not want the same thing happening here.
He said rises in power usage occur at half-time and full-time, when people put the kettle on or open the fridge door.
Mr Devine says staff at power stations in both the North and South Island will be watching the rugby, not for the games, but to know when to boost power supplies.