Democrats in the US Senate are rallying behind legislation curbing pay discrimination against women.

But the Bill stands little chance of surviving the debate.

Though Democrats run the chamber, they control only 55 votes and need at least five Republicans to overcome a procedural roadblock.

Senate Republicans derailed the plans — which would make it harder for companies to pay women less than men for the same work and easier for aggrieved workers to sue employers — in 2010 and 2012.

“Republicans stand opposed to pay equity at their own peril,” warned Democrat Senator Chuck Schumer.

He pointedly added, “We’re going to come back to this issue several times this year.”

The Bill would narrow the excuses companies can use for paying women less than men and bar would employers from retaliating against workers who share salary information.

It also would make it easier for women workers to bring class-action lawsuits against companies.

Women averaged 77 per cent of men’s earnings in 2012, according to Census Bureau figures.

Data shows that men out-earn women at every level of education in comparable jobs, with 62 per cent of the 3.3 million workers earning at or below the minimum wage last year being female.

President Barack Obama issued an executive order on Tuesday prohibiting federal contractors from retaliating against workers who discuss their pay.

He also ordered the Labour Department to require federal contractors to provide compensation data by race and gender.