Gay marriage advocates and Holocaust survivors have slammed Loree Rudd, sister for former Prime Minister, Kevin Rudd, for accusing some Labor members of being brainwashed by a "global gay Gestapo".

Mrs Rudd, who said she’ll quit the party if Labor supports marriage equality, believes the global push for gay marriage is just a propaganda ploy.

“I call them (marriage equality advocates) the global gay Gestapo,” The Australian quoted her as saying.

“It is the lobbying movement that is brainwashing people, particularly the young in the community that this (homosexuality) is an optional extra in life,” she said.

Her comments largely offended Australia's marriage equality advocates, who are now demanding apology from her.

Australian Marriage Equality National Convener, Alex Greenwich, said Ms Rudd's statement has no place in mature public debate and will incite hatred against supporters of equality.

"We call on those who oppose equality to condemn Ms Rudd's outburst, and for Ms Rudd herself to withdraw her comments and apologise for them", Mr Greenwich said.

"Ms Rudd has set back her cause by comparing supporters of civil rights to an organisation that was responsible for mass murder, including the mass murder of homosexuals."

Holocaust survivor, Mr Frederick Weisinger, who lives in Sydney and who wrote a moving submission supporting marriage equality to a 2009 Senate inquiry into the issue said:

"I spent three years in a concentration camp as a child, and I am horrified by this comparison between the Gestapo and ordinary citizens like me who just want to be treated equally."

"Before she makes such offensive comments, Ms Rudd should read about the horrors perpetrated by the Gestapo, particularly how it hounded, persecuted and killed homosexuals in large numbers."

Marriage equality advocate, Jackie Striker-Phelps, who is the wife of former AMA President, Kerryn Striker-Phelps, was also outraged.

"During the Second World War, members of my family had their human rights taken away and were murdered at the hands of the Gestapo", she said

"To compare the work of today's human right's advocates to the atrocities of those monsters is a shocking indictment on anyone making these claims."

Mr Greenwich added, "there is nothing 'optional' about being gay, it is who we are".

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