US President Barack Obama's ground-breaking support for same-sex marriage was met with applause from beleaguered gay rights campaigners in Asia on Thursday, but also with scorn from hardline opponents.

Rights and marriage for homosexuals barely figure on mainstream political agendas in the Asia-Pacific region, where traditional values dominate in many societies and sodomy remains illegal in some.

As in the United States, religious conservatives decried Obama, and most gay rights campaigners said in fact that the issue of wedlock was premature for now.

The region's only country where there is a serious debate about legalising gay marriage is Australia, but Prime Minister Julia Gillard said she was unswayed by Obama's change of heart and would continue to oppose it.

"I've made my mind up and my position on this is well known," she told reporters after Obama for the first time said that same-sex couples should be able to wed, igniting a fury of election-year debate in the United States.

Gillard said that when a bill calling for legalising gay marriage comes before the Australian parliament later this year, "I won't vote for it".

"This is a matter that people form their own views on, a deeply personal question, people will think about it, work their way through it."

Australia passed a legal amendment in 2004 explicitly defining marriage as between a man and woman, but activists believe pressure is mounting for Canberra to extend the right to same-sex couples.

Cheering supporters in Australia expressed hope that Obama's announcement would set a precedent that ripples across the Pacific.

Reverend Jeremy Greaves, whose liberal church in Darwin welcomes worshippers "regardless of sexual orientation", said: "I think for gay people within the church it'll come as a wonderful surprise and a great bit of news.

"I think for many gay people there's been a long struggle for recognition in the eyes of the church and the state, and I think this is another sign that times are changing for them," he told the Australian Broadcasting Corp.

In the mainly Catholic Philippines, the only country in the world apart from the Vatican which still bans divorce, President Benigno Aquino's government said cautiously that any change to the law would have to come from lawmakers.

But even the Progressive Organisation of Gays in the Philippines said it was not pushing for same-sex marriage, while hoping that Obama's advocacy would prompt Aquino to address other issues of concern.

"We are not asking for wedding bells soon, we are merely requesting the government to face up to the reports" of alleged discrimination against gays in the Philippines, the group's spokesman Goya Candelario said.

Neither is the issue of marriage high on the agenda for gay men and lesbians in India, "because they know it will upset more people", said Ashok Row Kavi, head of Humsafar Trust, a Mumbai-based group dealing with male sexual health.

"Already there is so much opposition, if they start talking about same-sex marriage, it will increase further. We can only fight this much at a time," he said.

But Kavi also acclaimed Obama as "a terrific president".

"I wish the Indian political class and state learn their lessons from Obama. Our traditional society is uncomfortable about these issues -- they don't know how it works."

But there was a vitriolic response from Vinod Bansal, spokesman for India's right-wing Vishwa Hindu Parishad group, who said gay marriage would "completely destroy our social fabric".

"It is Obama's view, it can't be endorsed by societies anywhere in the world. No religion permits same-sex marriages, neither is it beneficial in any way to society as a whole," he said.

"It will destroy the family system as well as the cultural and social values of different societies. What is morally wrong will never be accepted in India."

In Muslim-majority Malaysia, Ibrahim Ali, a parliamentarian and president of right-wing Malay group Perkasa, said that Obama's announcement would have no effect on public opinion.

But young Malaysians should nonetheless be educated against this "unnatural" lifestyle, which is against Islam, he said.