Almost one third of charities have had to either suspend or cut back on services in the past six months because of funding cuts and a drop in public donations.
A survey of 230 charities has found that 64% experienced a fall in their income over the first six months of this year.
It also revealed that 67% had experienced a sharp rise in demand for their services since the beginning of the year.
The Wheel, who conducted the survey, said the 900 charities it represented were, in effect, a safety net for the most vulnerable in society.
The children’s charity Barnardos recently suspended its services for a week and another week-long closure may be on the cards later this month.
Many charities, including the Irish Cancer Society and the Irish Heart foundation, have reported a significant decline in donations and some charities, such as the ISPCC, have made staff redundant since the beginning of the year.
Chief executive of The Wheel, Deirdre Garvey, said charities played an indispensable role in plugging the gaps in Ireland’s welfare system by providing essential public services like housing, support and care for people with disabilities and protection for the vulnerable and socially excluded.
"They are, in effect, a safety net. If charities are forced to close, the most vulnerable people in our society will have nowhere else to turn," she said.
According to The Wheel’s analysis, between 2009 and 2011, state funding for the charity sector fell annually by between 8% and 10%.
It also points out that the funding cuts were disproportionately higher for services provided by charities than those provided elsewhere.
Ms Garvey said the funding cuts, coupled with a fall in donations, had led to a situation where vital supports have had to be withdrawn at a time when they were most needed.
"We need to ask ourselves what does this say about us as a society?"
The Wheel, founded in 1999, works with community, voluntary and charitable organisations in Ireland, helping them to continue to deliver services with less resources.
"We help organisations to work collaboratively; to do more with less by pooling resources and focusing on the impact that they, individually, want to make," she said.
Ms Garvey said people should try and dig deeper into their pockets for charitable organisations but it was not all about money.
"Skills and time are just as important as cash to charities," she pointed out.