The Caritas Social Action Network (CSAN) has criticised the Government's plans to cap benefits at 1% for the next three years.
The Commons will vote this afternoon on the Welfare Uprating Bill proposed by Chancellor George Osborne.
The changes will affect income support and elements of housing benefit, maternity pay, some tax credits, jobseeker's allowance, sick pay and employment and support allowance.
CSAN, the social action arm of the Catholic Church in England and Wales, today warned against capping benefit increases significantly below inflation.
Chief Executive Helen O'Brien would make savings in the short-term but "hurt the poorest individuals and families in our society" and cause "greater human and economic costs in the future".
"Benefit payments should always be sufficient to cover the basics of family life including housing, meals, heating and clothing," she said.
"Already we are seeing a serious number of cases where this is simply not happening, and today's move will leave even more people struggling to afford such fundamental necessities."
The head of the Catholic Church in England and Wales, Archbishop Vincent Nichols, recently called upon parliamentarians to "ensure a safety net is always in place to protect essentials such as food and shelter for those who fall on hard times".
Rosemary Keenan, chief executive of the Catholic Children's Society (Westminster), said that the Bill would impact upon working families as well as the unemployed.
"It is hard for many of us to imagine what it is like for a mother to only have £1 left and know she still has to feed her children before the next payday," she said.
"Families facing in-work poverty rely upon Working Tax Credits and other benefits to help make ends meet, and will face serious hardship as a result of these restrictions."
Labour plans to block the move. Shadow chancellor Ed Balls said: "While millionaires get a tax cut, seven million striving working families are paying the price for David Cameron and George Osborne's economic failure.
"The best way to get the benefits bill down is to get the economy growing and people back to work, not hit striving families."
Work and Pensions Secretary Iain Duncan Smith has defended the measures as necessary to address the deficit.
He told Sky News: "We have to still continue to try and tackle the deficit left for us by Labour which is fuelling huge borrowing and will cost taxpayers enormously unless we get it under control.
"It is also about trying to do it in a way that is fair to those who are in work and are paying the taxes for those who are on welfare.
"The reality is they have seen their welfare payments rise far faster over the last six or seven years than anybody in work."
