The Charity Employees Benevolent Fund could close in June if it does not receive new funding soon.
Michael Brophy, a trustee of the fund and former chief executive of the Charities Aid Foundation, warned in a statement last week that the charity, which supports past or present charity employees and their families, faced closure because major charity employers had declined or ignored requests for support.
He told Third Sector on Friday that the charity had about £23,000 in the bank.
Brophy said its one paid employee, who works three days a week, earns about £24,000 a year, and the fund spent on average £1,500 a month on grants.
"We could have to close in June if things don’t change," he said. "We can’t go on like this unless we get something like £40,000 a year."
He said the organisation might consider going back to becoming a volunteer-run charity.
Brophy said the fund had received grants but needed a more regular flow of income, which could come from a per capita contribution from the major charity employers.
"It’s a minute amount of money that we’re asking organisations with a £100m turnover to contribute," he said.
But the only major charity that had agreed to make a regular contribution so far was the NSPCC, he said.
Brophy said charity staff were increasingly aware of the fund, with the number of applications for support increasing from about four or five a month last year to 15 a month this year.