Indian gay rights activists have voiced shock and outrage over public comments by Union health minister Ghulam Nabi Azad that homosexuality was a 'disease' brought to the country by foreigners.

Speaking at a national meeting on Monday of district and mayoral leaders on HIV/AIDS prevention, Azad stated that homosexuality was 'unnatural and not good for India'.

"It is a disease which has come from other countries," he added.

"Even through it is unnatural, it exists in our country and is now fast spreading, making it tough to detect it."

Prime Minister Manmohan Singh and the president of the ruling Congress party Sonia Gandhi also attended the meeting, but had left before Azad spoke.

Coming almost two years to the day after a landmark Delhi High Court ruling that decriminalised homosexuality, his comments prompted a storm of protest and calls for an immediate retraction.

"I think the minister needs to apologise immediately. He has insulted the entire homosexual community," said Mohnish Kabir Malhotra, a publicist and gay rights activist.

There was particular anger that the comments were made at a meeting of officials tasked with promoting and enforcing HIV/AIDS prevention policy at a grassroots level across the country.

"To have such a level of bias and ignorance expressed in that context about something so basic is very dangerous," said Mario D'Penha, a historian of the gay rights movement in South Asia.

Criticism also came from the United Nations AIDS agency, whose executive director, Michel Sidibe, attended the meeting in New Delhi.

"Consistent with the World Health Organisation's disease classification, UNAIDS does not regard homosexuality as a disease," Sidibe said in a statement.

"There is no place for stigma and discrimination on the basis of sexual orientation," he added.

Health ministry spokeswoman Shefali Sharan argued on Tuesday that the minister's quotes had been taken out of context and that when he spoke of disease, he was talking about HIV/AIDS and not homosexuality.

"He was not insulting anyone," Sharan said.

Aditya Bondyopadhyay, a lawyer and gay rights activist, said Azad's remarks would encourage those conservative groups and religious organisations who had vehemently opposed the 2009 High Court ruling.

"When a minister, and especially the health minister, says this in public, it conveys the impression that this is government policy, and that can have a huge impact on the lives of gay people who already struggle with official discrimination and police harassment," said Bondyopadhyay.

"The religious right will jump on statements like this to increase the amount of hate," he added.

Prior to the High Court ruling, homosexuality was illegal in India under a 150-year-old British colonial law that banned 'carnal intercourse against the order of nature'.

Conviction carried a fine and maximum 10-year jail sentence.

Anjali Gopalan, who heads the NAZ Foundation, a rights group that works with HIV positive people, said she was 'horrified' that a minister would use language that echoed the 1860 statute.

"In our line of work, the last thing we need is for some idiotic minister to make a statement like this," Gopalan said.

"Which planet is he living on? Either he has no understanding of this issue, or he just doesn't care," she added.

Although gay pride marches are now annual events in some major cities, homosexual culture remains shocking to many Indians, who often treat the topic as taboo.

It is not the first time Azad has courted controversy with his public statements.

In 2009, he was widely ridiculed after suggesting that bringing electricity to remote areas was crucial to population control, because villagers would spend more time watching television than having sex.