Research commissioned by the Department for Education found that average local council spend per child in need - where a child is identified as needing support services, such as early intervention family support or disability services - increased by 10 per cent, from £9,780 per year in 2010/11 to £10,780 per year in 2015/16.
However, researchers, who analysed local authority finance data found that spend per looked-after child by the average local council decreased by two per cent over the same period, from £46,740 per year in 2010/11 to £45,650 per year in 2015/16.
Overall, between 2010/11 and 2015/16 total spending by local councils on children's services was found to have decreased by nine per cent. England's councils spent £9.24m on children's services in 2010/11 but this fell to £9.01m by 2015/16.
The report also highlights huge variations in the amounts individual councils are spending per head on both children in need and children in care.
The biggest spenders on looked-after children were Torbay, which spent £73,541 in 2015/16, and Bournemouth, which spent £70,079.
While the lowest spenders on looked-after children were Manchester, which spent £31,249, and Liverpool, which spent £31,563.
Torbay was also the biggest spender per head on children in need, spending £22,720 in 2015/16. The lowest spenders on children in need were Tower Hamlets which spent £4,873 per head and Reading, which spent £5,199.
Earlier this month a survey by the Greater London regional branch of the Association of Directors of Children's Services found that councils in the capital are overspending on children's services by almost 10 per cent.
This year the Local Government Association has warned that councils face a £2bn spending gap in children's services by 2020 due to rising demand and cuts to central government grants.
Government data released in September revealed that the number of children in care is rising at its fastest rate in five years.