A Bill described as "a bonfire of child protection rights", which would let councils opt out of key legal duties to children, was debated on Tuesday.
The Children and Social Work Bill would let local councils apply to set aside children's rights and checks on care to try out innovative ways of working.
The government argues it is a bold approach to removing red tape.
But campaigners say allowing councils to opt out of these long-standing duties is risky and unnecessary.
The legal duties affected by the Bill relate to nearly all the social care services children receive from local authorities laid down in numerous acts of Parliament.
These include statutory rights on child protection, family support, children's homes and fostering, support to care leavers and services for disabled children.
About 50 organisations publicly oppose the proposed exemptions - including the British Association of Social Workers, The Care Leavers' Association, Women's Aid, Liberty and the National Association of People Abused in Childhood.
They have banded together to form a group called Together for Children to oppose the Bill, which was debated by a House of Lords committee on Tuesday.
The organisation said: "Children's social care laws have evolved over many decades, often in response to failures in care and protection but also because of new knowledge and understanding."
Carolyne Willow, director of independent children's rights organisation Article 39, said: "More than 107,000 members of the public have signed a petition opposing the plan.
"With such a radical and unprecedented change to children's law, it's not unreasonable to demand a Green and White Paper consultation.
"We have been unable to find any example of any other country which allows councils to opt out of their duties to very vulnerable children and young people, including those the state is directly responsible for by law
Acknowledgement: Extract from BBC news article byy Hannah Richardson BBC News education and social affairs report