The coalition Government has come under attack for welfare reforms which critics claim are punishing the poor and hitting women hardest.
Labour claim newly introduced cuts to child benefit, combined with a three-year benefits and tax credits squeeze, is a "huge assault" on millions of working families.
Research compiled by the Commons library for shadow equalities minister Yvette Cooper shows that 4.6 million women who receive child tax credit directly will be hit by a cap on welfare increases, according to the Guardian.
It comes as the Child Poverty Action Group published a report claiming changes to the way the Government is uprating benefits is a "poverty-producing" move that further hits the poorest.
The charity warns that, while pensioners have been given a triple-lock guarantee of a notable rise, the worst-off will face a "double lockout" that "cuts them loose from the cost of living and the mainstream of society".
Chancellor George Osborne announced last year that annual rises in most working-age benefits are to be capped at 1%, cutting a further £3.7 billion from the welfare bill, but insisted he would protect the vulnerable by continuing to increase carer benefits and disability benefits in line with inflation.
The charity warns that levelling the cap over each of the next three years would amount to a 4% real-terms cut in benefits on top of £18 billion of already announced cuts. It found welfare spending on workless families has been falling and warned that, under the changes, absolute and relative child poverty will increase.
CPAG chief executive Alison Garnham said: "It's wrong to punish the poorest and most disadvantaged in our society by cutting social security protection every time growth targets are missed while the better-off are protected. It really would be politics of the worst kind if, as reported, this Bill has been laid to create a political dividing line - we are talking about real lives, not political games.
"Depicting the neighbour with drawn curtains in the morning as a 'scrounger' to be scorned is a dangerous game to play. You may find it is a sick or disabled person, whose curtains are only drawn when their carer arrives, or a nurse who just got to bed after her night shift. This is a poverty-producing Bill that does nothing to reduce the need for support."
Prime Minister David Cameron has defended cuts to child benefit payments, which will see families with one earner on more than £50,000 lose some or all of the payment while households with two parents with salaries just under the trigger keep theirs, insisting the move was "fundamentally fair".