A youth support agency says some schools are breaching human rights by refusing to allow students to set up gay support groups.
Rainbow Youth says the refusal is a breach of human rights and another form of homophobia.
Education officer Serafin Dillon says she knows of four schools that have refused to allow students to set up the support groups.
Ms Dillon will not name the schools, but says staff told her that school authorities feared the groups could trigger an outbreak of homophobia.
She says the schools are not the same ones that recently banned same-sex couples at school balls unless they signed a contract confirming that they were gay or lesbian.
Post Primary Teachers' Association president Robin Duff says having gay support groups helps schools to embrace diversity. But though some schools do it very well, others have their heads in the sand, she says.
A Human Rights Commission spokesperson says some students have requested information about the issue. No complaints have been laid.
Education Minister Chris Carter says he would act swiftly if he knew any school was discriminating against students because of their sexuality.
Mr Carter says he had not been made aware of any such cases, and is confident schools know they must abide by the law, which means they cannot discriminate on the basis of gender, race or sexuality.