The Muslim Council of Britain (MCB), with more than 500 affiliated mosques, charities and schools, said on Tuesday it was “appalled” by the proposed legislation set out by the government last week.
The government has proposed that faith groups would be allowed to “opt in” to legislation if they want to conduct gay marriages.
However, the officially established Church of England and its sister the Church in Wales would be explicitly banned from doing so under the legislation. Both Anglican churches had expressed strong opposition to same-sex marriage.
The MCB is looking for the same degree of legal protection.
MCB secretary-general Farooq Murad said the Muslim community had also strongly opposed gay marriage and that he was seeking an urgent meeting with Culture Secretary Maria Miller to show her the strength of feeling among Muslims.
“No one in their right mind should accept such a discriminatory law,” he said.
“It should be amended to give exactly the same exemption to all the religions.”
The legislation will explicitly state that it will be illegal for the Church of England and the Church in Wales to marry same-sex couples, Miller told parliament when she set out the draft legislation.
Islam is the fastest-growing religion in England and Wales, 2011 census data released last week showed.
It increased by 75 percent in 10 years to 2.7 million adherents, or 4.8 percent of the population.
Anglicans and Roman Catholics, among other denominations, are expected to oppose the draft legislation, even with the caveats designed to meet their concerns.
But some religious groups, including Quakers, Unitarians and Liberal Judaism, are in favour of gay marriage.