The Justice Commission of the Conference of Religious in Ireland (CORI) has claimed the Government has betrayed the poorest people during its time in office.
Father Sean Healy said the gap between rich and poor has been dramatically widened as a "direct result of the Government's tax and social welfare policy".
He urged it to tackle poverty, inequality and social exclusion, but accused it of lacking the political will to do so.
His statement follows a report by the ESRI, published last week, which showed that the levels of deprivation had declined between 1994 and 1998, and relative income poverty had increased.
Father Healy pointed to growing housing waiting lists, the rise in the proportion of those living in relative income poverty and the increasingly pronounced two-tier health system, despite an almost doubling of the healthcare budget.
"Despite the abundance of resources, social exclusion has increased and the gap between the poor and the rest of society has widened." This development was not an accident, he said, and more than sufficient resources were available to tackle these problems effectively.
"Everyone could have and should have benefited but Government chose instead to use these resources to benefit the better off. The evidence suggests that the tackling of poverty, inequality and social exclusion was not considered a major Government priority."
In making its decisions, the Government had failed to honour the aims and objectives of the Programme for Prosperity and Fairness, he said. CORI is a social partner and was involved in negotiating the PPF.