THE coalition Government's welfare reforms are punishing the poor and hitting women hardest, critics claimed today.

Labour said cuts to child benefit which came into effect at midnight, combined with a three-year benefits and tax credits squeeze, was 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, one newspaper reported.

It comes as the Child Poverty Action Group published a report claiming changes to the way government is uprating benefits is a "poverty-producing" move that further hit 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".

It was also estimated the changes to tax credits could hit more than one-quarter of a million working Scottish families. Labour calculated that the average family stands to lose £279 under the plan.

Speaking before a Commons debate tomorrow, Shadow Scottish Secretary Margaret Curran said the Conservative-Liberal Democrat coalition is prepared to cut incomes of about 261,000 families.

She said: "The best way to get the welfare bill down is to get people back to work."

Chancellor George Osborne announced last year that annual rises in most working-age benefits are to be capped at 1%, cutting a further £3.7billion from the welfare bill, but insisted he would protect the vulnerable by continuing to increase carer and disability benefits in line with inflation.

Child Poverty Action Group warns that levelling the cap for three years would amount to a 4% real-terms cut in benefits on top of £18billion of already announced cuts.

It warned that, under the changes, absolute and relative child poverty will rise. Chief executive Alison Garnham said: "It's wrong to punish the poorest and most disadvantaged in our society every time growth targets are missed while the better-off are protected."

Prime Minister David Cameron said child benefit cuts, which will see families with one earner on more than £50,000 lose cash while households with two parents with salaries under the trigger keep theirs, was "fundamentally fair".