The deaths of 11 cows by electrocution highlights the need to stay on top of maintenance and on-farm safety, Federated Farmers says.
The cows were killed this week on a Dargaville farm after a disused power service line sagged onto a nearby 400-volt line, causing the old line to go live.
Northpower had disconnected the line to an old cowshed in March for safety reasons, but it was not taken down.
Northland Feds President John Blackwell said he understood it was the farmer's responsibility to remove the line.
"It was incredible luck no one else was hurt and there was no loss to human life," he said.
"My condolences to the farmer concerned. It must have been awful to see the animals like that."
The incident should drive home the message of safety first for any property manager or land owner, Mr Blackwell said.
"Even if people think lines are disconnected they can still be deadly. Get onto health and safety problems when you know about them - do not procrastinate."