The Society of St Vincent de Paul has said people who get help from the charity have no more to give the Government in next month's Budget.
It says that social welfare fraud is not a major problem although it supports measures to tackle it.
SVP's National President, Mairéad Bushnell, was speaking at the launch of the charity's pre-Budget submission.
Noting that demand for its services had almost doubled in the past three years, she urged the Government not to cut the incomes and public services that are a lifeline for those who seek its help.
She said that cuts made already to social welfare and child benefit rates have had a devastating impact on the people it assists and that further cuts - including the proposed flat-rate annual household charge - will push them further into debt and poverty.
Ms Bushnell said that while the society supported measures to tackle and prevent welfare fraud, its work with individuals and families indicated that fraud is not a widespread problem.
Instead, the complicated nature of the social welfare system results in anomalies, delays and barriers for individuals and families trying to access payments, she said.