Church leaders have condemned the benefit cap as "damaging" and warned that it overwhelmingly targets families with children.
It is estimated that 19 out of 20 families affected by the cap on benefits have children.
Just 14 per cent of those affected by the cap are unemployed and claiming Job Seekers Allowance.
In a statement today the Church leaders say it "cannot be morally acceptable to leave children without enough to live on."
More than a quarter of a million children have been affected by the cap since it was introduced in April 2013.
Their statement is released as the Government announced the cap, which limits the amount of benefits people of working age can claim, is to be set even lower, from £26,000 to £23,000 in London and £20,000 outside London.
From next Monday, the total amount a couple or a single parent can receive in benefits will be £442.31 a week or £1,916.67 per month in London and £384.62 a week or £1,666.67 per month outside London.
The Baptist Union, the Church of Scotland, the Methodist Church and the United Reformed Church united to condemn the cap.
Paul Morrison, policy adviser on behalf of the churches, said: "It is clear that the Benefit Cap overwhelmingly targets children – 19 out of every 20 families whose benefits had been capped have children.
"The lower Benefit Cap could be disastrous for tens of thousands more children throughout the country. We know, from our experience on the ground and the Government's own research that the Benefit Cap drives people into rent arrears, debt and hunger."
The Government claims that the benefit cap is designed to get people into work, but also acknowledges that most families affected have illness or caring responsibilities that prevent them from working.
Morrison said: "More than 2,000 single parents with babies under a year of age had their Housing Benefit cut because of the cap each month. Does the Government seriously expect that cutting Housing Benefit will make it easier for them to find work?
"It cannot be morally acceptable to leave children without enough to live on in order to pressurise their parents into work. This is doubly true if those parents have no prospect of moving into work because they are sick or caring for family members."
A YouGov survey commissioned by the Churches revealed that 61 per cent of UK adults believe that welfare benefits should be set at a level that allows families with children to cover their basic costs.
