An amendment to a broad immigration bill just passed by the US Senate Judiciary Committee, which would have allowed binational same-sex couples to sponsor their partners, was dropped in an effort to ensure that the bill passed.

The amendment ,which had the backing of President Barack Obama, was proposed by Democratic Senator Patrick Leahy on Tuesday evening, as he attempted to convince Republicans to support it, however some on the fragile bipartisan coalition said they would vote against the bill if the amendment was included.

The amendment also lost the backing of some Democratic members, who said they could not support it if it meant the downfall of the bill.

After the amendment was withdrawn, the committee passed the bill 13 votes to 5.

Last month lawmakers had expressed fears that including same-sex couples in the groundbreaking legislation could throw the bill, which is being pushed forward by a bipartisan effort, off course.

Currently, straight couples can sponsor their foreign-born spouses to obtain green cards, however there is no equivalent option for binational same-sex couples.

Advocates of adding gay couples to the key bill, estimate that around 36,000 couples already live in the US who are not able to obtain the necessary green card, with more living abroad because they cannot obtain the visa.

Back in February, Democratic Senator Patrick Leahy also proposed a separate bill which would allow US citizens to sponsor their same-sex partners for residency visas, however advocates recognised that the bill was unlikely to pass in the Republican controlled US House on its own, rather than being included in the larger, more comprehensive bill.