Leaders of six religions on Wednesday voiced concern that a debate on France's secular nature and Islam planned by President Nicolas Sarkozy's right-wing party could lead to confusion and stigmatisation.

The text signed by Roman Catholic, Protestant, Christian Orthodox, Muslim, Jewish and Buddhist leaders described secularism as "a pillar of our republican pact, a basis of our democracy, a foundation of our desire to live together."

"Let's take care not to squander this precious gain," they warned, saying it was "capital during this pre-election period, to calmly stay the course by avoiding lumping things together and the risks of stigmatisation."

"Debate is always a sign of health and vitality... But is a political party, even in power, the right authority to carry out the debate alone?" they wrote in La Croix daily.

Sarkozy, whose UMP party is trying to avoid losing votes to the far-right National Front (FN) ahead of next year's presidential election, in February called for a debate on secularism and the role of Islam in French society.

The call was swiftly taken up by the UMP which is on April 5 to hold a debate entitled "secularism and the place of religions, in particular Islam."

France's Muslim population of five to six million -- the largest in Europe -- has already voiced concern over the divisive debate.

Some members of the UMP also disagree with the debate which they say is taking the party too far to the right while also legitimising the FN's political agenda.

The six religious leaders said they were ready to reflect with "our country's authorities and forces so that the religious factor can be an element of peace and progress."

But "the acceleration of political agendas risks, ahead of important elections for our country's future, blurring this perspective and causing confusion that can only be detrimental.