Police say copper wire was cut from 10 transformers at Halcombe, north of Feilding, causing a brief outage on Tuesday night.
They are warning that the thieves are risking electric shock and increasing the risk of electrical fire, as well as disrupting the power supply.
Detective Sergeant Ash Gurney, from Palmerston North, says the theft of scrap metal has become a continuing problem and it is a dangerous game.
He is appealing for anyone with information on the thefts to contact police.
