India's development is being slowed by discriminatory practices against women such as child marriage, which stifle their potential to contribute to growth, peace campaigner Archbishop Desmond Tutu said this week.

"India is doing fantastically. I mean, they are complaining about 7% GDP growth. Imagine if you then enlisted the participation of 50% of the population. Women. Imagine what it would be," Tutu said.

"I think that India is poised to become a very significant player but that role would be greatly, greatly enhanced when women are given their proper place."

The Nobel peace prize-winning chairman of The Elders - a group of prominent people dedicated to addressing humanitarian issues - is spearheading a global movement called "Girls Not Brides" aimed at ending child marriage.

Gender experts said a girl under the age of 18 is married every three seconds - that's 10 million each year - often without consent and sometimes to a much older man, before she is mentally or sexually ready for such a relationship.

The practice is most prevalent in Africa, the Middle East and South Asia, despite laws in most countries banning it.