A landmark study into gender pay inequity, proves what most women already know they're valuable to businesses.

A world-first study by Motu Economic and Public Policy Research has found the value men and women add to their firms is statistically indistinguishable.

Yet, on average, a woman earns 84-cents for every dollar earned by a man.

Angela McLeod from Pay Equity Coalition told Rachel Smalley the research proves it's not a woman's fault she's paid less than a man.

"It's not her fault that men were negating the salary were not paid necessarily what that salary is."

LISTEN ABOVE AS ANGELA MCLEOD SPEAKS WITH RACHEL SMALLEY