Ofsted, the schools' inspections body, is becoming the "state regulator of religion", according to a coalition of Christian charities.
The joint statement from five separate charities urged Christians to oppose government plans to register and inspect out-of-school settings including church youth groups.
The department of education announced the plans last year which would force institutions that teach under-19s for more than six hours a week to register. The move is part of the government's counter-extremism strategy and came after concerns children were exposed to extremist views in a small number of Muslim madrassas.
However the charities warned that church youth groups could be inspected under the plans as they would force any institution that teaches children to register.
CARE, Christian Concern, the Evangelical Alliance, the Lawyers' Christian Fellowship and The Christian Institute have signed the statement which labels the plans an "unacceptable overreach of the state". A spokesman for CARE told Christian Today this coming together "demonstrates both the worrying nature of the government's plans and the strong resolve within the Christian community to stand up for the freedom to teach the Christian faith to the next generation without unnecessary State interference".
Published on Monday morning, the statement read: "Requiring churches in England to register before they are legally allowed to help children learn the Christian values our nation was built on is an unjustified restriction of religious liberty."
Education minister Nick Gibb has said inspections would only be carried out if complaints were lodged about a particular insitution. However the statement said the "scope for vexatious complaints is considerable, especially in the current climate of aggressive secularism and religious illiteracy. The experience of some Christian schools is that inspectors themselves can be ignorant of or hostile to Christian beliefs and practices.
"We do not believe Ofsted should become the state regulator of religion."
The statement went on to say it supported "reasonable measures to prevent terrorism". However it continued: "These proposals will lead to a loss of civil liberties and create a large bureaucracy that will divert resources away from restraining extremists who reject UK law. Such individuals will simply ignore or effortlessly circumvent the registration requirements.
"We urge the government to drop these proposals and develop a targeted, intelligence-led approach that will genuinely inhibit the activities of violent extremists."
CARE chief executive Nola Leach branded the plans a "wholly unwarranted undermining of religious freedom".
"We support tackling extremism, but not in this sweeping, overly broad manner," she said.
Colin Hart, director of The Christian Institute said: "The freedom to proclaim the gospel...must be protected, not undermined in the name of 'counter-extremism',".
CEO of Christian Concern, Andrea Williams, said "Christians are not terrorists".
The chairman of the Lawyers' Christian Fellowship said the plans may be in breach of human rights legislation while the Evangelical Alliance's head of public policy, Simon McCrossan said the proposals amounted to the "wholesale nationalisation of youth work and the state regulation of private religious practice."
He continued: "If implemented, there is a real risk churches will feel forced to step back from the valuable services they currently provide to young people across society."
Christian Today has contacted the Department for Education for comment.