SEOUL (AFP) - South Korean presidential front runner Moon Jae In came under fire Wednesday (April 26) for saying he did not like homosexuality, prompting angry protests at a campaign event by gay rights groups.

Moon, a former human rights lawyer of the centre-left Democratic Party, leads opinion polls by large margins before the May 9 presidential vote and has enjoyed wide support from young liberal voters.

But his remarks over homosexuality during a televised debate Tuesday left many of his supporters scratching their heads.

"I do not like it," Moon said when asked by a conservative rival whether he opposed homosexuality, adding he had "no intention" to legalise it or same-sex marriage.

Homosexual acts are not a crime in South Korea, but it remains a conservative and patriarchal society and does not recognise same-sex marriage.

Moon is a practising Catholic, a denomination normally associated with liberalism in South Korea.

Moon added that no one should be discriminated against due to their sexual orientation. But that comment did little to appease the LGBT (lesbian, gay, bisexual and transgender) rights activists who crashed his campaign event on Wednesday to protest.

They approached Moon after his speech, waving rainbow flags and shouting at him "Apologise for hate remark!" and "Are you opposing my own existence?"

Some were dragged away, with 13 detained for violating rules on public protest, according to pressure group Solidarity for LGBT Human Rights of Korea.

Gays and transgender Koreans live largely under the radar in a country that remains deeply conservative about matters of sexual identity and where many still regard homosexuality as a foreign phenomenon.