WASHINGTON - President Barack Obama declared Thursday that giving equal pay to women and men isn't just a women's issue, it's a family issue.

Obama appeared before a packed East Room audience for a ceremony to sign an equal-pay bill.

His entrance in the room was met with hearty cheers from the many labour and women's groups represented there.

House Speaker Nancy Pelosi, the first woman speaker in the history of Congress, and Secretary of State Clinton, were present. Clinton went further than any woman previously in her campaign for the presidency, although she ultimately lost the Democratic party competition to Obama.

The measure is designed to make it easier for workers to sue for decades-old discrimination. He said "this is a wonderful day."

The Lilly Ledbetter Fair Pay Act effectively nullifies a 2007 Supreme Court decision that said workers had only 180 days to file a pay-discrimination lawsuit.

It is named for a woman who said she didn't become aware of a pay discrepancy until she neared the end of her career at a Goodyear Tire & Rubber Co. plant.

Ledbetter was present at the ceremony.