Jewish pupils could become confused about their beliefs if they are forced to study faiths other than their own at GCSE, according to the National Association of Orthodox Jewish Schools (Najos).

Many Jewish schools have suggested they would drop GSCE religious studies if the government introduces the compulsory teaching of at least two faiths, Najos told the Department for Education.

Jewish schools, it stated, "would not feel comfortable focusing on the spiritual and practical aspects of another religion at this age and stage, as this could confuse the pupils with mixed messages, and challenge the ethos that their school is mandated - by parents and governors - to promote".

Under plans introduced by Education Secretary Nicky Morgan, the government wants schools to devote at least a quarter of the religious studies exam syllabus to a second faith.

Najos said: "Offering an alternative curriculum on the beliefs and spiritual underpinning of another religion could compromise the core ethos of the school and introduce confusion into the minds of our pupils."

It rejected the view that the only way to respect other religions is to study them at GCSE. "We believe passionately that Judaism at its core teaches respect and tolerance of others … so the study of Judaism will enhance pupils' respect and tolerance for other religions, rather than limit it," Najos said.

Its comments came in a formal submission as part of the government's consultation process.