The Director of Amnesty in Ireland has said the Government's Civil Partnership Bill further enshrines discrimination against gay people into Irish law.
Speaking on RTÉ's This Week, Colm O'Gorman said if the Government had concerns that there may be a constitutional issue with gay marriage it should bring forward a referendum.
He said the Bill discriminates as much against children than against gay people because it fails to protect them sufficiently through adoption rights for gay couples.
Mr O'Gorman is a gay man and a father of two children.
The Civil Partnership Bill was published on Friday and provides recognition to same sex couples, but it stops short of recognising civil marriage.
But reaction to it has been mixed and there was also strong criticism of the Bill among the 10,000 people at the annual Gay Pride march in Dublin yesterday.