The permit to build 26 wind turbines on 2280 hectares of land near Warrnambool was first granted to Global Power Generation Australia and Hawkesdale Asset in 2008.

The Victorian planning minister extended the permit in 2017 and then again in November 2020 after little-to-no work was completed.

But a 12-person community group called the People of the Small Town of Hawkesdale last year launched legal action in the Victorian Supreme Court, arguing the 2020 permit extension was invalid and an error of law.

A Supreme Court justice last August dismissed the challenge, stating the Hawkesdale group did not have a standing in the proceeding and the planning minister's permit extension was valid.

The association applied for leave to appeal the decision, arguing the judge made an error when determining the association did not have a special interest in the case.

The group also contended the Supreme Court justice failed to recognise the permit extension was invalid.

But three Court of Appeal justices on Thursday found there were no grounds for appeal and leave was refused.

"The evidence that the wind farm would affect the population level of Hawkesdale was both scant and speculative," the justices said in their written judgment.

"Moreover, there was no evidence that the impact of the wind farm on the population of Hawkesdale was a 'shared' concern of all the members."

The Supreme Court judge was also correct in finding the permit extension was valid, the court of appeal justices said.

The People of the Small Town of Hawkesdale were ordered to pay the costs of the planning minister, Global Power Generation Australia and Hawkesdale Asset.

The community group did not oppose the orders.

Australian Associated Press