Geoff Reid is worried about the effect of LED lighting on New Zealand's moths.

LED street lights will save money, but could come at a cost to native moths, says one environment-lover.

All older, yellow, high-pressure sodium lighting in Auckland is to be replaced with new light-emitting diode (LED) street lights by about 2025.

The first stage of fitting 44,000 LED residential street lights, has been under way for the past 18 months.

MATTHEW CATTIN/FAIRFAX NZ The Puriri moth is endemic to New Zealand's north island.

The lights use just a third of the electricity the older style lights use, and last four to six times longer. They have the potential to save the city $32 million over the 20-year life of the lights.

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But Geoff Reid wasn't glowing about it, saying some of the lights could negatively affect New Zealand's more than 2000 species of moth, as the tone of the light changes from golden yellow to white.

"Moths are really important in our ecosystem. They are kind of these central key species because they not only provide food for birds, they pollinate plants and also provide food for other insects," Reid said.

He said the new LED street lights, measured in kelvin, sit at more than 4000 while the current bulbs are around 2200. He said anything over about 2800 kelvin is bad for moths who are drawn to the blue light.

"They extract moths out of the ecosystem. It wears them out and they also congregate in one area around a light and what we're finding is mice are just cleaning them up."

Roughly 90 per cent of the moths are endemic to New Zealand with an estimated 400 species in Okura Bush on Auckland's North Shore near where Reid lives.

"What we're really concerned about is we have not had the chance to do any studies in Okura Bush. We could have 400 species in the bush and we don't have any light pollution. So, what we're facing with development, it's going to have a negative effect," Reid said.

"But it's not just about looking after Okura Bush, moths are so special to New Zealand. We should be saying we can't have any of these type of lights in New Zealand."

Reid suggested, if LED lights were used they needed to be a lower kelvin and the bulbs should have directional shielding and sensors should be considered.

"We're not saying all LEDs are bad. Just that we need to make sure they are the right ones. Amber rather than glarey bright white blue"

Reid had approached the Hibiscus and Bays Local Board to bring the issue to their attention and chairwoman Julia Parfitt said she'd found it fascinating.

"LEDs seemed to be the best thing since sliced bread. I hadn't realised the effect on moths," she said.

But street lights fall under Auckland Transport jurisdiction, rather than local boards and an AT spokesman previously said AT believed LED lighting made the roads and footpaths safer for traffic and pedestrians.

He acknowledged the white light could take some people time to adjust to the difference.

AT implemented a policy in 2012 that all new lights on pedestrian-dominated roads would be LED.