The society has gone into administration
The Treasury has a "moral duty" to help those who face losing savings with the Presbyterian Mutual Society, Enterprise Minister Arlene Foster has said.
The administrator. Arthur Boyd, had told PMS members they were unlikely to get all their money back.
Mrs Foster said the issue was discussed by the Executive and ministers are hoping to meet with Gordon Brown.
She that that the UK government "must act" to help members of the society.
"The Executive has done everything it can within its powers to assist the Presbyterian Mutual Society. It does not have the same options open to it as the UK Government in terms of depositor protection," Mrs Foster said.
"The UK Government must act now to assist the members."