Members of Action on Dementia Sunderland, who broke away from the Alzheimer's Society's Sunderland branch, are taking legal advice to see if they can retain use of the building.
The group was founded last month after the society announced it was changing its branch structure into a regional one.
Ernie Thompson, who helped found the branch in 1987, said it was unfair that the building, which was bought eight years ago with donations from local people, would no longer be under local control.
"People gave money on the understanding that it would be used in Sunderland," he said. "Now it turns out that isn't the case."
Ruth Sutherland, acting chief executive of the society, said it had received no formal notification of legal action. "The society continues to operate in the area and has plans for expanding service provision," she said.
- See Letters, page 10.