that teachers and school leaders should do more than pick up the phone.
According to Alan Wood, president of the Association of Directors of Children's Services and director of children's services at Hackney Council, teachers should in some circumstances consider meeting parents themselves or arranging additional support.
He added that in more serious cases, headteachers could "use their authority" to ensure that their concerns had been followed up by the police or local authorities. Social workers should even be based in schools, he said.
"People think, `This is a problem, [so] I'll give it to somebody'," he said. "Reportage is not enough. You can't simply say, `I told someone and nothing happened.' There has to be more."
Mr Wood acknowledged that many schools already took their responsibilities seriously. But he said he was concerned that Mr Cameron's announcement could encourage teachers to pass the buck, and that the threat of prosecution could "encourage everybody working with children to simply pass concerns up the line".
"They'll think, `We need to protect ourselves first by passing on an issue'," he said, adding that financially stretched social services departments were already facing a rise in referrals.
Instead, Mr Wood said, teachers considering referring a case to the local authority should ask themselves what a social worker could do that other people couldn't.
Protective measures implemented by social workers should be supported by in-school interventions, he added, saying that this should be part of a "new understanding" about "what it is reasonable to expect schools to do in terms of children's welfare".
"You can't divorce the fact that responsibility, accountability, governance and decision-making are all moving to schools. Funding has followed, and therefore services have to follow, and we have to be clear about that.
"It needs to involve the Department for Education talking with representatives of schools and local government and hammering out an agreement, a concordat, so everybody is clear about what the expectations are," Mr Wood said.
Last week, TES revealed that the NSPCC had been granted "whistle-blowing status", meaning that school employees who are dismissed or treated unfairly after raising concerns with the children's charity could be given legal protection. John Cameron, the charity's head of child protection operations, said he hoped it would encourage teachers to report concerns.
"We know that junior staff in particular, but other staff as well, are anxious about challenging their employers if they feel there's something untoward about how they have responded to a child welfare matter," he added.