By politics.co.uk staff
Today will be a "Black Wednesday for millions of families across Britain", shadow chancellor Ed Balls has said.
The beginning of the new tax year will see some of the government's spending cuts begin to bite into family budgets, with a freeze on child benefit claims taking effect and cuts to child support and other tax credits, like the working tax credit.
All benefits will become linked to the Consumer Price Index (CPI) rather than the Retail Price Index (RPI), which Labour says will cost a family with one child £33.80 in child benefit and a family with three children £75.40 this year.
Writing for the website Labour Uncut, Mr Balls said women and children would be hit the hardest by the tax changes.
"David Cameron promised to lead the most family-friendly government ever and George Osborne said we're all in this together," he wrote.
"So why are their changes to tax and benefits coming into force today hitting women harder than men and taking so much support from children, with families on low and middle incomes being hit the hardest of all?"
Labour estimates the cuts to childcare support will leave families up to £1500 out of pocket this year.
"This little noticed change will have a huge impact on hundreds of thousands of families, but particularly women with children who work part time and on low pay," Mr Balls wrote.
"But cuts to childcare support make no sense at all if it simply makes it harder for parents to go out to work - as the Office for Budget Responsibility has warned - and so ends up costing the taxpayer more."
The shadow chancellor also criticised the deputy prime minister's focus on the rise in the income tax threshold.
"Once again we can expect Nick Clegg to this week trumpet an income tax cut for some on lower incomes as a key achievement of the coalition," he wrote.
"But the truth is that the increase in the personal allowance is a fig-leaf for what's really happening to families."