Meridian Energy's appeal against an Environment Court decision, which declined consents for an Otago wind farm, has been referred back to that court by the High Court.

The wind farm proposed at the Project Hayes site on the Lammermoor Range, about 70 kilometres north-west of Dunedin, would be the largest wind farm in the southern hemisphere with 176 turbines.

Consents were granted by the Central Otago and Otago Regional Councils in 2007 but declined by the Environment Court last November.

Meridian's appeal against the Environment Court decision was heard in the High Court, Dunedin, in June.

The High Court decision, released yesterday will allow Meridian to appeal the Environment Court decision.

Justices Chisholm and Fogarty have told the Environment Court to reconsider its decision, and given direction about what extra evidence should be called.

Central Otago Mayor Malcolm Macpherson told the Otago Daily Times yesterday he was surprised at the strength of the High Court's support of Meridian's appeal.

"The Environment Court may well have to allow the original application and Project Hayes could be back on again," Mr Macpherson said.