New Zealand Windfarms, owner of the Te Rere Hau wind farm near Palmerston North, has reported a heavy financial loss after writing down the value of its assets by more than $30 million.

Based in Christchurch, NZ Windfarms' only operating asset is the 97 turbine wind farm on the Tararua Ranges, which was completed in mid-2011.

While the company's income from electricity sales more than doubled in the year to June 30 2012, lower than budget wind strength, a weaker view of wholesale prices in the future and restrictions placed on the operation of the wind farm prompted it to review the book value of its assets.

This resulted in a write-down of $30.7m, causing the company's net losses to balloon to $24.6m, six times the loss of the previous year.

Chairman Wyatt Creech, a former National Party MP said the impairment was "very substantial" and followed an in-depth review by the company's board of directors.

Last year the Palmerston North City Council sought an Environment Court declaration on whether Te Rere Hau complied with the noise conditions of its resource consent.

In July, the Environment Court made a declaration which would require NZ Windfarms to take action to mitigate noise effects, such as increased monitoring.

NZ Windfarms has appealed the decision but repeated today that reaching a deal with the council was its preferred option.

"NZ Windfarms is committed to ensuring that the Te Rere Hau wind farm's operations contribute positively to the community and are fully compliant with the resource consent conditions," Creech said.

Shares in the company were unchanged at 15c, valuing it at $43.2m.

The company has previously announced that it is undergoing a strategic review as it no longer intends to develop further wind farms, instead focusing on being a single wind farm operator.

Creech said NZ Windfarms had engaged in discussions with parties potentially interested in buying Te Rere Hau, although as yet there had been no "concrete proposals".

Vector, best known as the owner of Auckland's electricity lines, owns 22 per cent of NZ Windfarms.

- © Fairfax NZ News