Former New York City Mayor Ed Koch told MSNBC's Thomas Roberts on Thursday that Republicans will regret blocking a vote on a gay marriage bill.

GOP leaders in the New York Senate on Wednesday and again on Thursday discussed behind closed doors whether to bring a proposed gay marriage bill to the floor for a vote.

On Wednesday, the Assembly easily approved the measure, providing momentum for the issue and notching up the pressure on the Senate to act. Lawmakers in the 62-member Senate are evenly divided on the measure. A tie would mean a second defeat in the chamber in as many years for proponents.

Koch, who earlier in the year recorded a video ad urging New Yorkers to support Governor Andrew Cuomo's plan to make New York the sixth – and most populous – state to legalize gay marriage, discussed the measure as a footnote during an interview on MSNBC.

When host Thomas Roberts asked Koch for reaction on the bill, the 86-year-old lifelong bachelor responded: “Well, I have been, and continue to be, a supporter of same-sex marriage, because it's simply unfair that if you are a heterosexual couple you get 1,000 benefits under the federal law, primarily tax benefits, and if you are a same-sex couple living together you get zippo.”

Koch went on to say Republicans would regret blocking the vote.

“I think that they will rue the day if they don't allow a vote to take place and if the votes aren't there to pass it,” he said.