Matthew Reed, chief executive of the Children's Society, said:
This Bill will punish millions of children and families already struggling to make ends meet.
Two-thirds of families affected - over six million - have children.
As a result of today's move, life will be harder for families from all walks of life, including 300,000 nurses and midwives, 150,000 primary school teachers and 40,000 members of the armed forces.
Families already struggling to provide their children with food or a winter coat, or heat their homes are being pushed closer to the brink.
Child poverty blights lives and is a scar on our society.
Today's 'hardship penalty' punishes working families on low incomes as well as those looking for work, paving the way to a rise in child poverty.