Religious leaders have reacted with anger at plans to consider making new faith schools offer at least a quarter of places to children who do not share their beliefs.
Ministers believe the measure could help ease racial tension by breaking down barriers and encouraging inclusion.
They also want to give more parents the option to send their children to faith schools which have a reputation for academic achievement and good discipline.
The move is likely to affect Islamic schools most, which represent the growth area for new faith-based schools.
Tahir Alam, education spokesman for the Muslim Council of Britain, warned it would be opposed.
"Imposition is not a good way of progressing the integration agenda," he said.
"It is confrontational and it impinges on parents' rights. If they want to send their child to a particular school it is their choice to do so.
"This goes contrary to parental choice where parents send their child to the school that best serves their needs."
Mr Alam, who is also a Birmingham school governor, claimed imposing quotas was to go down a dangerous road.
"Where do you stop? The vast majority of schools in the country are almost completely white - do you impose quotas on them to encourage racial harmony?
"This is a very impractical way to do things and fraught w ith implementation difficulties."
Mr Alam added: "If this measure was introduced it would have a disproportionate affect on the Muslim schools because it applies to new schools not existing ones.
"The only schools that are up and coming in this way are Muslim schools."
The Catholic Church also strongly spoke out against imposed quotas on numbers in any of its schools.
The Most Rev Vincent Nichols, Archbishop of Birmingham, said: "We are vehemently opposed to the imposition of quotas on Catholic schools, because it would mean turning away Catholics and could well lead to more division."
A spokesman for the Birmingham diocese added: "Many Catholics and parents throughout the diocese of Birmingham want Catholic schools to be for Catholics."
The Government is considering making all religious schools adhere to the 25 per cent non-faith quota after the Church of England last week said it would voluntarily do so.
The CofE believes it is important to open up its s chools to the wider community.
Mary Edwards, diocese director of education, said: "I would argue that a school that has youngsters from a variety of backgrounds means they learn about each other and each other's faith. We want all our youngsters to grow up respecting members from other faiths who are growing up in the Birmingham area."
Education Secretary Alan Johnson is expected to announce the new measure this week.
Under the plans, local authorities would be given powers to require that a new faith school admits 25 per cent of non-believers where they deem it "reasonable".
The measures are also expected to make clear that where there is strong local opposition, councils must secure the consent of the Education Secretary.
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