Northland electricity company Top Energy says a scrub fire near Kaikohe has cost more than $200,000 in repairs and lost power.
The fire at Ngawha last week destroyed 60 hectares of bush.
It also destroyed about 50 metres of fibre optic cables to a geothermal power plant, sidelining it for four days.
Top Energy chief executive Roger De Bray says that could have been prevented if there had been firebreaks on the land.
