The head of the U.N. agency promoting equality for women says her office is mounting a major campaign for equal pay for women, who get 24 percent less than men on global average and around 30 percent less for those in Asia.

Phumzile Mlambo-Ngcuka says the agency which she heads, U.N. Women, will put the issue before heads of state and the private sector.

She says estimates show gender inequality in employment across Asia alone is costing $45 billion a year, with 45 percent of working-age women outside the labor force compared to 19 percent for men.

She says if female employment were to match male employment, per capita GDP would rise 19 percent in Southeast Asia and 27 percent in the Middle East and North Africa.