Stockholm - Sweden's centre-right government has failed to agree on new legislation allowing same-sex couples the right to marry, but will press ahead with legislation to that effect, Prime Minister Fredrik Reinfeldt said Wednesday.

Opposition from the Christian Democrats, one of the four parties in Reinfeldt's four-party coalition, has forced the other three parties to go it alone and seek support from the opposition.

Reinfeldt said his conservative Moderate Party, the Liberal Party and Centre Party would present a bill on same-sex marriage with an amendment stating it would take effect as of May 2009.

"We don't have the same view among the parties in the Alliance (for Sweden)," Reinfeldt told Swedish radio news.

The premier said that while he wanted the bill to pass, he also "respected different opinions," including possible dissenting voices in his own party, the main force in the coalition that took office two years ago.

The opposition Social Democrats, Green Party and Left Party also support same-sex marriages and have earlier indicated they were preparing to introduce their own proposal if the government does not make a move.

Adding pressure, some members of the ruling coalition recently said they were prepared to vote with the opposition.

A poll of 1,000 people published in January showed that 71 per cent of Swedes favoured allowing same-sex couples to marry, while 24 per cent were against. Another 6 per cent were undecided or doubtful.

Since 1995, same-sex couples have been able to form a union in Sweden via registered partnership. The law was later amended to allow them to adopt children.

Last year, the government asked various organizations and bodies to comment on proposals to change current legislation.

The central board of the Church of Sweden, a Lutheran church, said it would accept changes to marriage laws that offer same-sex unions the same legal status as traditional marriage. However, the term "marriage" should be reserved for the union between man and woman, the board - elected by the Church Assembly, the highest decision- making body in the church - said.

Some 80 per cent of Sweden's 9 million people belong to the Church of Sweden. It was disestablished in 2000, receiving the same "faith community" designation as other faiths, such as the Pentecostal, Baptist, Roman Catholic, Jewish and Muslim.

Currently, 39 faith communities have the right to conduct legally- binding marriage ceremonies. They would likely have to reapply for that right should new marriage laws be adopted.

Leaders of the Swedish Humanist Association, the Roman Catholic church, and three free churches including the Pentecostals and Baptists said Monday they backed introducing a civil ceremony that would be legally binding for all.

People of faith could then subsequently "decide to let their faith community conduct a blessing ceremony," they said in the joint op-ed piece in Stockholm daily Svenska Dagbladet.

"Churches and faith communities would regain full right to decide over a ceremony with deep religious and cultural roots, without state intervention into the content or a forced theological compromise," they added. (dpa)