The Association of Directors of Children's Services says there has been a "lack of focus" and investment in the wider children's workforce resulting in a shortage of staff and insufficient training opportunities.
These roles have "borne the brunt of a decade of austerity", says the ADCS in a policy paper Building a Workforce That Works For All Children.
This says a "coherent workforce strategy" is needed to address capacity issues and ensure that training is up to date and readily available. Improvements in support also need to be properly funded.
The proposed strategy should be developed by a national children, young people and families workforce lead and overseen by a group involving representatives from across government as well as the ADCS and other children's sector organisations.
A children's workforce lead is necessary as national government policy and investment for the children's workforce operates in silos, across a number of departments, says the policy paper.
"The sector lacks a clear voice to advocate for the whole children's workforce at the national level," it states.
"This role would be best placed in the Department for Education, which leads on the majority of children's policy matters, to promote the need for and value of integrated working across the whole workforce."
- Children's workforce qualifications and training guide
- Research: The Early Years Workforce in England - A Comparative Analysis
ADCS president Stuart Gallimore says that currently much of the government's children's workforce focus and investment is on social workers and teachers.
"It is right that there is focus and investment in these professions, but this should not be at the expense of the wider children's workforce," said Gallimore.
"There is a multitude of professions and services that are key to improving the lived experiences and outcomes of children and families often before they reach the threshold for children's social care, from youth workers, family support workers and school support staff to health visitors and more.
"All are deserving of further government attention and, crucially, investment."
He added: "Children don't live in a siloed world and so it follows that we cannot improve their outcomes in a holistic way working in a siloed way."
Gangs, mental health, domestic abuse and substance abuse are among issues where the wider workforce can offer important support, says the ADCS policy paper.
"These are complex and multifaceted issues which require a workforce that is able to respond at the earliest possible opportunity; responding effectively cannot be the responsibility of statutory services alone," it states.
The ADCS is also calling for greater investment in the early years workforce.
This can be paid for through money saved by reducing the eligibility criteria for the government's 30 hours free childcare for working parents, which is currently available to households earning up to £199,000 a year.
Other recommendations include a greater focus on leadership training for aspiring and serving directors of children's services, in particular in supporting black, Asian and minority ethnic children's professionals looking to step up to senior leadership roles.
There should also be a greater use of apprenticeships to fill gaps in training and all training for children's professionals should have a common set of shared values.
Personal advisers working with care leavers should also be offered a higher level apprenticeship, adds the ADCS.
The Department for Education has been contacted for comment.