Accord, which brings together the Association of Teachers and Lecturers, Christian think tank Ekklesia and the British Humanist Association, will launch on Monday as new rules come into place making it legal for voluntary controlled schools to be headed by a person of specific faith and for voluntary aided schools to discriminate against non-teaching staff on the basis of their religion.
The coalition alleges that faith schools discriminate against students and teachers of different faith and that they damage community cohesion.
Accord's Chair, the minister of Maidenhead Synagogue Rabbi Dr Jonathan Romain, said that the group's aim was to ensure that schools welcome children from all backgrounds.
The Faith Schools' Providers Group, however, slammed Accord's assertions in a joint statement.
"Faith communities entirely refute the allegation that faith schools are discriminatory, or that they represent a divisive force within British society," the statement read.
Signatories of the 'Faith schools in the system' statement include the Chief Education Officer of the Church of England Board of Education, the Rev Janina Ainsworth, and the Chief Executive of the Catholic Education Service, Oona Stannard.
Other faith representatives to sign the statement include the Chair of the Jewish Leadership Council, Henry Grunwald, Chair of the Association of Muslim Schools, Dr Mohamed Mukadam, and the director of the Network of Sikh Organisations, Dr Indarjit Singh.
They said that Accord's criticisms do "a disservice to the huge value that faith schools add to our state education sector and the extent of appreciation that parents and students have for these schools".
They insisted that faith schools accept children from non-religious backgrounds and other faith groups, and are often more ethnically diverse than comprehensive schools in the same area.
The group also denied that the strong performance of faith schools was down to 'cherry-picking' the best students and said that faith communities "will go out of their way" to offer financial help to less well off students.
Faith schools enjoy the support of the Government, which sees them as a means to raise the education standards in deprived areas. In September 2007, the Government and religious groups established a new partnership, 'Faith in the System', as an affirmation of their commitment to work together to "build bridges to greater mutual trust and understanding and to contribute to a just and cohesive society".
The majority of the 6,850 faith schools in England are Roman Catholic or Church of England.
The Faith Schools' Providers Group concluded in its statement, "As thousands of students are starting a new school year, it is disappointing that some commentators see fit to attempt an inaccurate character assassination of some of the brightest success stories of our education system."