Gordon Brown must protect savers who risk losing thousands in the collapse of the Presbyterian Mutual Society, Stormont's deputy first minister said today.
Martin McGuinness and first minister Peter Robinson have made a direct appeal to the prime minister to intervene in the crisis.
Many people face the prospect of losing much of their life savings as a result of the PMS being placed in administration late last year.
While the government has guaranteed deposits up to £50,000 in banks caught up in financial meltdown, it has made no such undertaking for mutual societies such as the PMS.
Stormont's leading ministers have now added their voices to mounting calls on Mr Brown to widen the protections.
"Obviously there is a very difficult situation facing many people who invested in the Presbyterian Mutual Society and we in the Executive are very sympathetic to their plight at this time," said Mr McGuinness during Assembly question time.
"And we do believe there is a responsibility to Gordon Brown and the British government to recognise their responsibility and to recognise the responsibility that the British government has in particularly has to ensure that those people do not incur loses to what for many are their life savings."
The Sinn Fein deputy leader said he and Mr Robinson have written to the prime minister seeking an urgent meeting on the issue.
While the PMS is not directly linked to the Presbyterian church, its moderator yesterday urged congregations to sign a petition appealing to Mr Brown to take action.
Rev Dr Donald Patton claimed the government's decision to underwrite the banking system had led to the crisis at the PMS.
"We need thousands of signatures to indicate to the government the widespread concern of the church at large and to support those placed in personal difficulty by the events which were triggered by the government guarantee to the banking system," he said.
"This will also strengthen our hand as we make representation to government."
A week ago administrator Arthur Boyd wrote to 9,500 investors recommending that they accept a proposal which he said would mean they received some money back.
If this is to go ahead, more than half those affected must vote to back it by the end of the month.
During question time at Stormont, Mr McGuinness also revealed that he and Mr Robinson would be seeking a meeting with UK business secretary Lord Mandelson to ensure local companies receive assistance to help them weather the ongoing economic downturn.