South Africa's Nobel peace laureate Archbishop Desmond Tutu says he will never worship a "homophobic God" and will rather go to hell.
The retired archbishop was speaking at the launch of a UN-backed campaign in South Africa to promote gay rights.
Despite same-sex relationships being legal in South Africa, it had some of the worst cases of homophobic violence, UN human rights chief Navi Pillay said.
Archbishop Tutu, 81, is a long-standing campaigner for gay rights.
'Toilet brush attack'
He retired as Archbishop of Cape Town in 1996, but has remained the moral conscience of the nation, correspondents say.
Same-sex relationships are illegal in more than a third of countries around the world and punishable by death in five, Ms Pillay said.
In Africa, homosexual acts are still a crime in 38 countries, according to the rights group Amnesty International.
"I would refuse to go to a homophobic heaven. No, I would say sorry, I mean I would much rather go to the other place," Archbishop Tutu said at the launch of the Free and Equal campaign in Cape Town.
"I would not worship a God who is homophobic and that is how deeply I feel about this."
Archbishop Tutu said the campaign against homophobia was similar to the campaign waged against racism in South Africa.
"I am as passionate about this campaign as I ever was about apartheid. For me, it is at the same level," he added.
Ms Pillay said gay and lesbian people in South Africa had some of the best legal safeguards since apartheid ended in 1994, but they still faced brutal attacks.
Last month, a lesbian was found dead, having been sexually assaulted with a toilet brush.
"People are literally paying for their love with their lives," she said, AFP news agency reports.
The UN would push for gay rights to be recognised in countries where they are illegal, Ms Pillay said.
"I constantly hear governments tell me, 'but this is our culture, our tradition and we can't change it'... So we have lots of work to do," she added.
Archbishop Tutu won the Nobel peace prize in 1984 for campaigning against white minority rule in South Africa.