Ministers gave the go-ahead to Viking Energy's development on the mainland in April after estimates it would generate £566 million of capital expenditure and tens of millions of pounds in annual income for the island. But campaigners opposing the 103-turbine development have lodged a petition with the Court of Session in Edinburgh calling for a judicial review of Energy Minister Fergus Ewing's ruling. A hearing has been set for October 24 for judges to decide if ministers have a case to answer.
Campaign group Sustainable Shetland said it felt let down that there was no public inquiry into the development despite the level of opposition. The Government's energy consents unit that dealt with the application received 2736 objections along with 1114 letters of support for the project.
In his judgment on April 4, Mr Ewing said no public inquiry had been called as the council did not object to the plan.
But opponents say the council was too closely involved in the project, with all but one councillor also sitting on Shetland Charitable Trust, which is the joint partner in the Viking Energy development with Scottish and Southern Energy.
Sustainable Shetland said it was challenging the ministers' decision "on grounds including the impact on protected species and landscape and the failure to hold a public local inquiry".
But the wind farm's backers said the energy consents unit handled the application process with extraordinary care.
Opposition group vice-chairman Frank Hay said: "If a public inquiry had been held and it had gone against us we would have accepted that."
If the Court of Session decides there is a case to answer it will set a new date for a hearing.
A Scottish Government spokeswoman said: "Scottish ministers are considering this petition and whether to be represented at the hearing."
Meanwhile, plans for 10 wind turbines in an area of natural beauty have been scrapped after 50 objections. Vattenfall had assessed the viability of building the wind farm near Creetown within the Galloway Hills, but there was unease locally to the proposal for Blackmyre Moor.