Analysis by the Local Government Association has found that growing demand for social care services, coupled with funding cutbacks, are forcing three quarters of councils to overspend on their children's services budgets, by a total of £605m in 2015/16.
The LGA says extra money is having to be channeled into urgent support for children and families in crisis, which is leaving little to invest in early intervention.
Funding for early help has been further hit by a £500m cut in the Early Intervention Grant to councils since 2013. The LGA predicting this will drop by a further £183m by 2020, representing a 40 per cent reduction over 10 years.
"The fact that the majority of councils are recording high levels of children's services overspend in their local areas shows the sheer scale of the funding crisis we face in children's social care, both now and in the near future," said the LGA's children and young people board chair Richard Watts.
"Councils have done everything they can to respond to the growing financial crisis in children's social care, including reducing costs where they can and finding new ways of working. However, they are at the point where there are very few savings left to find without having a real and lasting impact upon crucial services that many children and families across the country desperately rely on."
He added: "The reality is that services for the care and protection of vulnerable children are now, in many areas, being pushed to breaking point. Government must commit to the life chances of children and young people by acting urgently to address the growing funding gap."
Between 2005/06 and 2015/16 the number of children subject to child protection enquiries increased from 71,800 to 170,000 and the number on child protection plans increased by around 24,000 over the same period.
The LGA has previously warned that councils face a £2bn funding gap by 2020 due to the scale of demand for children's services.
The County Councils Network, which represents county councils in England, is calling for the government to give the funding crisis in children's social care equal priority as the financial problems facing adult social care.
In addition, the CCN is calling for reform of local government funding, saying that under current arrangements county councils receive £292 less per head than the average London council.
"The services vulnerable children desperately need to live a life most of us take for granted are coming under unsustainable pressure in rural areas, as we have seen unprecedented demand at a time when our budgets have drastically been reduced," said Ian Hudspeth, CNN children's services spokesman.
Anna Feuchtwang, National Children's Bureau chief executive, said the double hit of increased demand and funding cuts that children's services are facing is placing an "intolerable strain on the system".
"Stepping in early to help families is essential for turning vulnerable children's lives around and saves money in the long run. But with support for early intervention services in long-term decline, families often only receive help when it is too late to keep a family together," she said.
"We urge the government to reconsider its strategy for funding children's social care and to recognise the severe consequences that year-on-year cuts are having for the children and families that rely on them."