Police have used pepper spray against a protester chained to machinery at a Santos coal seam gas facility in the Pilliga, a move opponents say will likely fuel community anger against the project.

Kerri Tonkin, a 47-year-old grandmother from South Australia, said she had her hat and glasses ripped off by a policeman during a protest on Monday. The officer then sprayed capsicum spray into her eyes, mouth and face from just one inch away.

Kerri Tonkin, one of the anti-CSG protesters who says she was pepper-sprayed by police. Credit:The Wilderness Society

"I've got a lot of damage to my eye," Ms Tonkin told Fairfax Media. She also said she received scratches to her face and had her arm and shoulder wrenched by the policeman who later told her she was lucky not be Tasered.

"I don't think pepper spray was necessary," Ms Tonkin said, adding that at the time she was chained to machinery with another woman and unable to move. "It was a totally peaceful project - there was no verbal, we didn't even swear."