The amendment to the proposed legislation, tabled last week by Conservative peer Lord Nash, will allow third parties nominated by the Education Secretary to initiate care or adoption proceedings in court.
Care and adoption proceedings are currently only taken by local authorities.
Legislation is already in place for the secretary of state or a third party nominee to intervene where a local authority’s children’s services are found to be consistently failing.
But the government said there “may be a question” about whether a family court would be willing to recognise a third-party nominee as if it were a local authority. It added that the amendment simply “clarifies” existing powers.
The NCB has called for the amendment to be thoroughly debated as it could, in practice, pave the way for children’s services to be outsourced to private firms or the voluntary sector in the future.
Enver Solomon, director of evidence and impact at NCB, said: “We need to have a wide debate and discussion about whether this is the best way to improve outcomes and keep children safe.
“There is an agenda of government moving to outsource failing children’s services, but I don’t think it is an issue that is getting much visibility or is being articulated very clearly.
“This amendment opens up provision to a multiplicity of providers.
“You could have private companies such as Serco running services, or social enterprises or charities.
“It might improve practice, but, on the other hand, it might not improve practice.”
A briefing note on the amendment, issued by the Department for Education states that the ability for third parties to take court proceedings would only be used in failing authorities.
“As is the case at present, they would only be used in cases where a local authority has persistently failed both to meet standards and to demonstrate capacity for improvement,” the document states.
“Even in Doncaster, one of the most persistently poor performing authorities for children’s services, the secretary of state has not found it necessary to use these powers.
“Should it, however, become necessary in the future to remove children’s services functions from a local authority to secure swift improvement and protect children, the secretary of state must have available the full range of powers that parliament itself intended.”
In August, it was claimed that the government is considering taking failing children’s services out of local control at a handful of councils.
Since June 2009, Ofsted has given 20 local authorities a grade of "inadequate" for overall effectiveness of safeguarding and child protection.
Concerns about allowing third party providers to take court proceedings coincide with separate concerns about the privatisation of social work.
In order to allow several pilot projects of GP-style social work practices to continue, the government is triggering Part 1 of the Children and Young Persons Act 2008, which will allow any local authority to delegate children’s social care responsibilities to voluntary or private providers.