Bob Katter has shown an appalling lack of sensitivity in describing gay marriage as something that "deserves to be laughed at and ridiculed," the Australian Greens said today.

"Let's not forget the member for Kennedy once claimed there were no gays or lesbians in his electorate," Greens' spokesperson for LGBTI, Sen. Sarah Hanson-Young, said today.

"Marriage equality is no laughing matter for the thousands of loving same-sex couples who are being denied the right to marry. And it's certainly no laughing matter for their families and friends who want to see them celebrate their love and commitment through marriage.

"I also understand that at this same rally one speaker alleged that marriage equality will open the door to marriage between paedophiles and children.

"The debate about marriage equality is about giving equal rights to relationships between consenting adults - to suggest otherwise is absurd and highly offensive .

"The members of Parliament present at today's rally, including Kevin Andrews and Barnaby Joyce, should distance themselves from these offensive claims.

"Whatever your views on this reform, there is no place in the debate for these kind of insensitive and outrageous comments. This kind of language insults thousands of same-sex couples across the country, along with their friends and families."