A conservation body is objecting proposed plans to build 16 wind turbines on Mynydd y Gwair and adjoining commons.
The Open Spaces Society has objected to the RWE npower renewables proposal to swap land in the common with land on the edge.
The group says the energy company has planning permission for the development but, because it is to be sited on registered common land, the developer needs the additional consent of Welsh ministers for works on common land.
They said in addition, the company has sought consent to construct a road and temporary fencing on the common.
Kate Ashbrook, general secretary of the Open Spaces Society, said: “These monstrous turbines and their associated infrastructure will devastate these magnificent, breezy commons above Swansea.
“This open moorland is on the doorstep of a huge urban population, and is of immense value to the people of Swansea.
“There are rights to walk and ride over the whole area and the views are tremendous.
“We do not believe that the applicants have met the necessary tests for development on common land, and we shall fight these proposals on behalf of all who enjoy these magnificent commons.”
An RWE npower renewables spokesman said: “This is exactly what the consultation process is for – to enable groups like the Open Spaces Society to have a say and bring their views to the table.
“All relevant comments raised during the process will be forwarded to us by the Welsh Government planning inspector, to respond in due course and help inform their decision making process.”