The pro-demutualisation Leek United Members Group is to report the board of the society to the Building Societies Commission, claiming it improperly rejected members requisition notices.
The group claims the board's rejection shows lack of understanding of the society's rules.
Group chairman Erwin Bengry says: "The press release which the board issued incorrectly stated the society's rules. Members who lodged perfectly valid requisition notices were further confused to receive the letter from the chief executive Mr McFadden.
"Approximately 50 members have telephoned to voice their concern about the board's actions and failure to comply with the society's rules."