Turkish President Recep Tayyip Erdogan on Monday declared that women are not equal to men and launched a bitter attack against feminists in Turkey, claiming they reject the concept of motherhood.

Speaking at a summit in Istanbul on justice for women, the devoutly Muslim president said that biological differences between women and men meant they cannot serve the same functions in life.

"Our religion (Islam) has defined a position for women (in society): motherhood," Erdogan told an audience of Turkish women including his own daughter Sumeyye.

"Some people can understand this, while others can't. You cannot explain this to feminists because they don't not accept the concept of motherhood."

He recalled: "I would kiss my mother's feet because they smelled of paradise. She would glance coyly and cry sometimes.

"Motherhood is something else."

He went on to say that women and men cannot be treated equally "because it is against human nature."

"Their characters, habits and physiques are different.... You cannot place a mother breastfeeding her baby on an equal footing with men.

"You cannot get women to do every kind of work men can do, as in Communist regimes.

"You cannot tell them to go out and dig the soil. This is against their delicate nature."

Erdogan was apparently referring to the practice during and after World War II for women in Communist states like the USSR to do heavy manual work in factories or in roles such as tram drivers.

The Islamic-rooted government of Erdogan has long been accused by critics of seeking to erode the country's secular principles and limiting the civil liberties of women.

Erdogan has also drawn the ire of feminist groups for declaring that every woman in Turkey should have three children and with proposals to limit abortion rights and the morning-after pill.