The New York Senate’s vote on gay marriage has been delayed again.

The bill has already been approved by the Assembly but amendments to give religious groups more protection are being discussed.

If passed, it will make New York the sixth US state to grant marriage equality, giving national gay rights campaigners a substantial victory.

Last night, lawmakers stayed in the Senate until 11pm, when Senate leader Dean Skelos said he was ending the session “for the health of members”.

In today’s session, lawmakers must consider several other bills before getting to the issue of marriage equality. The legislative session ends on Monday.

The bill is thought to be just one vote short of approval. Republican Senators are pushing Governor Andrew Cuomo to strengthen religious protections.

In meetings with the governor, Senators have reportedly expressed concern that religious groups could be at risk of legal action if they refuse to hold ceremonies for gay couples.

Speaking to reporters yesterday, Mr Cuomo said: “I think the entire conference is looking at this language and the whole conference wants to make sure that they feel confident that if it comes out and if it passes, that it protects religion.

“And as I’ve said before, I’m pro-marriage equality, I’m also pro-First Amendment. I’m pro-church-state separation and I’m pro-religious freedom, so I also have the same concern.”

Last night, President Obama told gay Democrat supporters in New York that gay couples “deserve the same legal rights as every other couple in this country”.

The event, the timing of which was a coincidence, was the president’s first fundraiser with the gay community.

The president, who has endorsed civil unions in the past, stopped short of calling for full marriage equality.