About 100 Iraqi women led by a minister protested in central Baghdad against a Governing Council proposal to scrap the secular family affairs code and place it under Muslim religious jurisdiction.
"I am outraged how the decision was taken," public works minister Nesrine al-Barwari told AFP.
"Iraq is a multi-ethnic and multi-confessional society and the Governing Council must be more sensitive to this and it must create a true dialogue when it comes to these matters."
Barwari said the council has formed a committee to consider turning the proposal into law but that she and other women leaders in Iraq wanted to make their opposition heard to both the council and the US-led coalition.
She said women also demand greater representation in any future Iraqi government.
At the demonstration in Ferdus Square women stood behind banners that read: "No to discrimination between men and women in the new Iraq," and "We reject decision 137 (of the Governing Council) which undermines the Iraqi family and society."
Zakia Khalifa, an activist, said the new law would "take away women's rights."
"Even Saddam Hussein's family laws are better than this one," she said.
Iraq's 1959 civil code governing family affairs was considered the most progressive in the Middle East, making polygamy difficult and guaranteeing women's custody rights in the case of divorce.
Since 1991, Saddam's secular regime made some changes to the code to bring it more in line with Muslim laws but its essence remained the same.