Ministers must honour commitments to make housing and childcare more affordable to prevent household budgets being further squeezed after voters backed Brexit, a report has warned.
The estimated minimum cost of raising a child over 18 years is £151,561 for a couple and £182,589 for a lone parent, according to research for the Child Poverty Action Group.
It adds this has increased from the 2015 figures of £149,800 for a couple and £167,300 for a single parent.
A report for the charity by Loughborough University's Donald Hirsch also argues that the rise in the minimum wage - labelled the National Living Wage - from £6.70 to £7.20 for workers aged 25 and over still results in low-paid families who work full-time being unable to earn enough to meet their needs.
These are judged on what the public believes is a minimum socially acceptable standard of living in the UK - including food, clothing and a week's self-catering holiday, among other things.
Parents are still facing difficulties despite flat inflation and cheaper core costs, such as food and energy, the report adds.
It concludes: "A particularly striking aspect of the trends identified by this report is that, in several ways, the position of lone parents is worsening relative to couple parents - or to put it another way, it is becoming increasingly difficult to bring up a child alone."
It also states: "In the uncertain times ahead following the European Union referendum, public budgets are likely to be put under renewed pressure.
"In order for this not to make low-income families worse off still, commitments to address some of the highest family costs, particularly in housing and childcare, need to be honoured.
"This means developing an adequate supply of affordable housing.
"For childcare, the promise of additional free hours will need to be made a reality, which means funding it at a level that makes it attractive for suppliers to provide places, or going further and supplying public childcare places directly at low or no cost.
"These are essential investments in our children's futures."
Mr Hirsch said the number of families with "less than the minimum" continues to grow.
He explained: "This is partly because the parents we talk to agree with governments and social commentators that early childhood experiences are essential for life chances, and include items such as good quality childcare and after school activities in the 'minimum' budgets that they construct for families.
"These things have become more expensive in recent years, while wages have stagnated and benefits have fallen.
"If family living standards continue to be squeezed in this way, those on the lowest incomes will find it ever harder to give their children a good start to life."
Alison Garnham, Child Poverty Action Group chief executive, said: "With inflation low and key household costs falling, parents on the new so-called 'National Living Wage' might have expected some breathing space.
"But our research shows they can't even cover the costs of basics for their kids - and much of that is down to soaring childcare costs and rents that are nigh-on unmanageable if you're on a low wage."