Northpower is also appealing to scrap metal dealers to "do the right thing" and inform police if they are suspicious about people offering copper for sale.
The company, which spends about $20 million a year on its lines network, is owned by its 54,000 customers and any extra costs associated with the thefts ultimately come out of their pockets.
Northpower thinks tough economic times are to blame for the desperate thefts.
Copper has been stolen from Whananaki, Helena Bay, Ngunguru and Port Rd in recent weeks.
"We are working with police right now to identify a pattern to these thefts but we have been hit six times in the past fortnight alone, mainly on the east coast," Mr Dawson said.
"We need to put a stop to it now because while there is a significant cost of replacement, safety is our primary concern as these thefts have potential to put our field crews and customers at risk in the event of a fault. This is because the ability for a fault current to flow, and in turn operate protection devices, is reduced."
He said in the event of a fault, the earth wire allows high fault current to flow, which in turn allows protection devices to operate, but cutting into the electric ground wires, if there is a loose connection on the pole, could result in a person being killed or seriously injured.
The thefts could leave a home vulnerable to a power surge, and subsequent fire.
"We are talking voltages up to 11,000. It's a very hazardous occupation chopping into that kind of voltage," Mr Dawson said.
He said destroying the integrity of the earth system also posed a danger to staff making repairs as the copper ground wire is designed to protect lines, equipment and transformers on the poles.
