society as support for state-funded religious education continues to grow.
Dr Jonathan Romain, minister of the Maidenhead synagogue, said the expansion of faith schools was a "retrograde step" which would ghettoise the UK.
His comments came as it emerged that the Government has backed proposals to open two more Jewish faith schools - bringing the number of state-funded primaries and secondaries to 38.
Work is due to begin next month to expand the Akiva school, a private primary in Finchley, north London, after its application to join the state sector was approved.
Earlier this year the Government also backed proposals for the first maintained cross-communal Jewish secondary in Barnet, north London.
Andie Newman, from the Movement for Reform Judaism, a charity established to support the less orthodox synagogues, said: "The number of Jews in this country is declining by about 1 per cent every year. This creates anxiety - parents want to ensure their children have a strong Jewish identity to reverse this decline."
Some commentators predict as many as nine out of 10 Jewish children could be educated in Jewish schools within a decade.
Dr Romain said: "I believe it is a retrograde step, which is not in the interests of the country at large. My fear is that this will lead to a fragmented generation, growing up ignorant of each other."
However, Alan Shaw, the head of Moriah day school, a state primary in Harrow, north-west London, this week criticised the "negative image" given of faith schools.
"My own children went to a Jewish school and have had no problem integrating with the wider world," he said.
"Our pupils go to sports clubs, visits to other schools and they all take part in national charitable events - there is no sense of isolation at all."