Johann Lamont, deputy leader of Scottish Labour, told MSPs in a Scottish Parliament debate that funding cuts had left voluntary organisations in crisis.
Lamont said charities had been left alarmed by recent reductions in spending. "Warm words will not sustain volunteers or the voluntary sector," she said.
Lamont was particularly critical of the decision to withdraw funding from youth volunteering initiative Project Scotland.
The Liberal Democrats and the Conservatives also spoke out against the decision to axe Project Scotland funding.
An SNP spokeswoman later told Third Sector that Scottish Labour's claims were "bizarre".
"As they know, the SNP in Government launched a £1.7m Resilience Fund for the third sector last week, as part of the 37 per cent increase in funding to the third sector by the Scottish Government.
"The new fund has been developed with the third sector and will help organisations meet the pressure of the downturn.
"Far from abandoning Project Scotland as Labour innacurately claims, the minister set out in the Scottish Parliament the work he is undertaking with Project Scotland to see how it can play a role in improving employability. Labour's scaremongering attacks are ill-informed."