Workers' union Usdaw claims to have been told that Kwik Save will go into administration today [Friday] unless staff continue to work for nothing.
Usdaw said Kwik save employees are facing "a very difficult situation", after the supermarket chain made a plea during a court hearing for seven more days to put together a refinancing package to save the company.
"Members are being asked by their store managers if they are willing to work for another week unpaid," said Usdaw's national officer Joanne McGuinness.
"Our members will have to make their own minds up whether their own circumstances means they can go another week without wages.
"If they agree then they face another week of mounting debts but if they don't then the company goes under and they then have to wait to get money from the DTI."
The future of Kwik Save has been uncertain since new management took over the company some 11 weeks ago. Kwik Save has already closed 81 of its branches, with the remaining 145 stores under threat.
McGuinness asked Kwik Save to make short-term loans to unpaid staff "so they can at least put food on the table for their families".
The court in Manchester will continue its hearing into whether Kwik Save is allowed further time to restructure today.
