Amnesty International has warned of a likely legal challenge if Northern Ireland is left as the only part of the UK without marriage rights for same-sex couples.

Speaking in advance of a vote in the Northern Ireland Assembly on same-sex marriage, due to take place on Monday, Patrick Corrigan, Amnesty International's Northern Ireland Programme Director, said:

"States may not discriminate with regards to the right to marry and found a family, on the basis of sexual orientation or gender identity.  That obligation is clear in international law. This means that marriage should be available to same-sex couples in Northern Ireland just as it appears it soon will be in other parts of the UK.

"Equally, the right to adopt, for instance, should be available without distinction based on sexual orientation or gender identity.

"The UK authorities cannot abdicate that responsibility not to discriminate and Northern Ireland politicians should not leave local same-sex couples with inferior rights to the rest of society.

"Should politicians fail to act, there could be a legal challenge on the basis of inferior treatment of same-sex couples in Northern Ireland with regards to the right to marry and found a family.

"Sadly, it appears that some politicians prefer to abdicate their responsibility on questions like this, leaving it instead to judges to take the right decision."