The pilot was uninjured. Power was disrupted to about 18 homes.
The second accident occurred on Wednesday just after 6am, involving another Robinson R44 helicopter conducting spray operations on the Mahia Peninsular.
The helicopter's skid struck wires and contacted the ground heavily.
The pilot, a 43-year-old man, was the only person on board the helicopter when it crashed.
He received moderate injuries and was flown to hospital for assessment.
The CAA is investigating both accidents with the co-operation of the two operators involved.
"Any aircraft flying at low levels is at risk of a wire strike," the CAA said.
"Agricultural aircraft, whether fixed wing or helicopter, are especially susceptible due to the nature of the work they do.
"Wire strikes are preventable, but only with a well-planned safety programme to identify hazards and put mitigations in place."
On Tuesday there was also a fatal helicopter crash near Kaikōura, which claimed the lives of Andrew Hamish Davidson, 60, and wife Lin Chen, 39.
Two of their children were injured - including son Angus - along with a third child.
