New Zealand's biggest power companies are facing the costly task of replacing thousands of concrete power poles.
Currently, there's nearly 13,000 of them dotted around the country, all in need of repair or replacement.
It's because the metal reinforcements, found in most concrete power poles, can rust and weaken over time.
Victoria University of Wellington engineer Joseph Bailey thinks he's created a way for power companies to take the guess work out of the equation.
He’s been developing his prototype as part of the Robinson Research Institute’s power pole research.
"Currently, the only signs are rusty water leaking out of a pole, or rusty concrete falling off. But sometimes the worst rust, and therefore the most damaging to the structure of the pole, is on the inside, unseen," Mr Bailey said.
His invention uses electromagnetic fields to detect rust, meaning companies will be able to decide which poles need replacement more accurately.
"It's going to become unaffordable to replace them all at once, and so some way that we can extend their life will be really beneficial."
The Commerce Commission sets the standards electricity companies have to meet.
"Like all infrastructure - it's important that it's well looked after - that's why we have a key interest that these companies are asset managing their networks," said Nick Russ, general manager at the Commission.
He says the Commission wants to ensure New Zealanders are getting the best quality service.
"It's an important role policing that... We have had a number of companies that have not met their standards that we're currently investigating."