Meridian Energy's application to build a 176-turbine farm on the Lammermoor Range which would be the country's largest is awaiting a ruling by the Environment Court.

Dr Macpherson said the outcome of the application could have national consequences for future energy policy.

A decision had been expected in May but Dr Macpherson said an apparent delay in the court's decision-making process was not a cause for concern.

"It's a bellwether. This decision is much larger than Central Otago."

"Hayes, if consented and Meridian build it, will change the wind farm scene in New Zealand. It could show they are consentable and buildable. It is of a scale that it could change the context of wind farms. We will have to wait and see what the court comes up with."

Detractors believe the farm, if built, could have serious consequences for the visual landscape in a remote part of Central Otago.

If rejected, energy firms will have to think about the future viability of wind farms on a national scale, he said.

An Environment Court spokesman said the Project Hayes application was reserved and the court was working on it as quickly as possible.

The project was originally granted consents by the Central Otago District and Otago Regional councils but it was appealed in the Environment Court.