Power has been restored to Canterbury centres Tekapo and Albury, after an unplanned power outage left thousands of households in the dark overnight.
Transpower has completed repairs to its Tekapo-Timaru line after wires were severed by a helicopter on Monday.
A crop-dusting helicopter on private land near Cave took out two of its conductors - one with the rotor and one with beam of the helicopter - about 10.25am, Transpower said.
About 3500 households were affected by the outage.
Transpower said local lines company Alpine Energy was now in the process of reconnecting its customers in Tekapo, Albury, and surrounding areas.
Transpower executive general manager of grid delivery Mark Ryall said he was grateful Alpine Energy was able to back feed power supply to some areas in Albury and Fairlie, as well as source additional generation for key sites in the Tekapo township.