UK Government benefit changes will significantly increase child poverty, following years of decline, according to the Scottish Government.

An additional 50,000 children will be impoverished by 2020 compared with 2011, the Scottish Government said in its annual report for child poverty in Scotland.

Deputy First Minister Nicola Sturgeon said only independence would allow the Scottish Government to make the substantial difference needed to reduce child poverty.

But Labour welfare spokeswoman Jackie Baillie said the figures demonstrated the Scottish Government's lack of ambition and determination to use the power it already has.

The Child Poverty Action Group (CPAG), a UK charity led by Labour peer Ruth Lister, said the SNP administration's policies should be more ambitious.

Relative child poverty, where families live on below three-fifths of Scotland's annual median wage, dropped in Scotland between 1998 and 2005, plateaued for a few years and dropped again between 2009 and 2012, the Scottish Government report found. Longer-term UK figures suggest relative child poverty is at its lowest since the mid-1980s, it said.

Increased access to benefits, which are controlled by Westminster, has driven much of the reduction, with child tax credits and working tax credits pushing up family incomes, it said.

The Conservative-Liberal Democratic coalition's welfare changes will increase the income of some poorer families, relative to others, but this will be counterbalanced for some by cuts to other benefits, the report found.

"Changes to child benefit are estimated to affect 91,000 families with children in Scotland, with an average loss of income of £1400 per year," it said.

"The Institute for Fiscal Studies also estimates the relative child poverty rate in Scotland will increase significantly by 2020, rising to 22.7%. This would account for an additional 50,000 children in Scotland living in poverty."

Ms Sturgeon said the Scottish Government was working with local authorities, the NHS and others... to help support young people into work."