In a radical change to the old Parental Leave Act of 1998, the new act states that people in a "relationship of domestic dependency", including samesex partners, can take up to three days paid leave in a year for urgent family reasons such as a sudden illness or injury.

What is termed 'force majeure' leave was included in the 1998 act, but same-sex or cohabiting couples could not avail of it. The breakthrough followed an amendment to the act proposed in the Dail last March.

Legal sources specialising in constitutional law confirmed that, while same-sex partners can take discrimination claims under equality legislation, this is the first time they have been given a positive legal right.

"This is the first significant breakthrough for same-sex couples in Ireland and would be an important step on the way to affording them full legal status, " said one legal expert.

Last week, justice minister, Michael McDowell, speaking at a conference on the legal status of same-sex couples in Dublin, said a "political consensus was emerging towards introducing legislation in this area". McDowell said he was committed to introducing such legislation "during the lifetime of this government".

But strong opposition to legalising same-sex couples was evident at the same conference when several members of the Ancient Order of Hibernians shouted down McDowell's address and threw copies of the constitution at him.