A group of teachers and parents will gather in Dublin today to launch a new organisation calling for a No vote in the referendum next Friday.

Educators for Conscience say that if the Yes vote is passed, teachers may be forced to teach material that is age inappropriate.

The group says that the proposal has serious consequences that have not been properly dealt with in the public debate.

It claims there is evidence from other countries where, after the introduction of same-sex marriage, teachers came under pressure to radically change their education practices.

It says if the referendum passes, "gender-neutral marriage would be elevated to a new status in the Constitution, and employees of the State would be obliged to protect that new model of marriage".

"As teachers, our fear is that for example, a teacher who gives preferential treatment to a view of marriage as between a man and woman over a same-sex marriage will be seen to be discriminating", it adds.

Spokesperson Kevin Leavy says they believe their rights in the classroom will be severely compromised if the constitution is changed.