The Local Government Association (LGA) says "urgent" action from government is needed to tackle the £2 billion funding gap it has projected children's services will face by 2020.
The LGA says more money is needed to meet rising numbers of children in care - Department for Education figures published last month show the care population has reached its highest level in five years. Without more money, councils will struggle to provide essential services for vulnerable children and families, it adds.
The association's new report, Bright Futures - getting the best for children, young people and families, also calls on ministers to reverse cuts of more than £1bn in council's early intervention funding to enable greater investment in early help support for vulnerable families.
Launching the report at the National Children and Adults Services conference in Bournemouth today, Richard Watts, chair of the LGA's children and young people's board, said: "Children's services are at a tipping point with growing demand for support combining with ongoing council funding pressures to become unsustainable.
"With 90 children coming into care every day, our calls for urgent funding to support these children and invest in children and their families are becoming increasingly urgent.
"Children's services face a £2 billion funding gap by 2020. If nothing is done to address this funding gap crucial services that many children and families across the country desperately rely on will be put at risk.
"We are calling on the government to use the Autumn Budget to commit to fully funding children's services and invest in improving services to ensure vulnerable children get the appropriate support and protection they need."
Other recommendations for government in the report include creating a "cross-Whitehall ambition for children and young people, articulating the role all departments will play". This should be supported by an "impact assessment" of all government policies and legislation on children and young people.
The association also reiterated calls for the DfE to devolve a proportion of its £300m budget for improvement and innovation in children's social care to sector-led initiatives to support children's services improvement.
The Budget takes place on 22 November.