More than two-thirds of UK teachers have raised concerns about the safety and well-being of their pupils within the past year, a survey suggests.
Primary staff were most likely to speak up, with 71% having done so in the past year, the poll for the NSPCC and Times Educational Supplement found.
And 81% of the 1,200 employees surveyed had reported an issue at some point during the last five years.
But some education leaders felt social services failed to act quickly enough.
"Getting the attention of children's services is really difficult," said Russell Hobby, general secretary of the National Association of Head Teachers.
Many local authorities were very overstretched, he added.
"Reporting safeguarding issues is almost a daily occurrence, but to have a social worker come in and deal with it is quite rare."
Overall only 15% of the staff questioned said they had never reported an issue.
The NSPCC said the majority of teachers who raised concerns were worried about signs of possible neglect, including children being constantly hungry, dishevelled, disorganised or tired.
The charity's head of child protection operations, John Cameron, agreed a "lack of resources and the pressures social workers are under" meant there was often a delay in councils tackling such problems.
Sometimes the school was best-placed to provide support to pupils, he said, "particularly where an intervention is required before it becomes a serious issue".
But Mr Hobby stressed it was difficult for teachers to assess on their own whether there were more serious problems.
"The line between pastoral care and social work is not an easy dividing line," he told the TES.
Education Secretary Nicky Morgan said there was "nothing more important than keeping young people safe, and this survey confirms the vital role that teachers play in highlighting safeguarding concerns".
The survey was carried out to coincide with the launch of new website by the NSPCC and the TES to help schools in England check whether their procedures for safeguarding pupils meet current standards.