Imran Hussain from Child Poverty Action Group has warned against changes to tax and benefits in the next few years, as they could cause UK poverty to rise.
His concerns come following a report released by Unicef which has revealed the UK placed 14th overall in Europe when it comes to child inequality.
The study, 'Report Card 13,' compares the poorest children's lifestyles to typical children in the UK, ranking the results against other countries.
The UK tied with Germany, Greece and Hungary, but was ranked in last place of 37 countries when considering children's healthy eating.
And Hussain fears proposed new legislation would worsen the situation.
He told Julia Hartley-Brewer: "If the tax and benefit changes to be implemented in the next few years happen, what we're going to see is poverty rise, which is associated with worse outcomes for children.
"The report's big finding is we should be investing in good childhoods for our children, meaning they are happier, healthier and better educated, which should in turn strengthen our economy.
"The big warning in the report is the evidence shows child wellbeing is associated with poverty, and in the UK our social security system is critical in tackling poverty."