In January, the Iraqi parliament amended the 1959 Personal Status Law to allow people to choose between religious or civil regulations for family matters such as marriage, inheritance, divorce and child custody.

Under the amendment, the Shiite Endowment Office established the "Code of Jaafari (Shiite) Rulings on Personal Status Matters", which was approved by parliament.

The amendment allows a man to convert his marriage contract to be governed by the Shiite religious code without informing his wife.

Ghazal, who only gave her first name, told HRW she received a court summons notifying her that her ex-husband had filed a lawsuit to retroactively apply the Shiite personal status code and terminate her guardianship over her 10-year-old son a decade after their divorce.

"It is unacceptable that someone marries under a law that protects the rights of women and children, and then, more than a decade later, manipulates the law to strip those rights away," the woman, who said she ended her marriage after it turned "violent", told HRW.

The new code also allows husbands to divorce their wives without informing them or seeking their consent and "automatically transfers responsibility and care of children to the father after age seven", HRW said.

While a wife can ask that no polygamy or divorce can take place without her consent, the marriage or divorce remains valid even if the husband breaches these conditions.

Sarah Sanbar, an Iraq researcher at Human Rights Watch, said that "the new Personal Status Code further institutionalises discrimination against women, legally relegating them to second class citizens".

"It takes away women's and girls' agency over their lives and instead gives it to men. It should be repealed immediately."

An earlier version of the amendment faced a backlash from feminists and civil society groups over fears it would lower the minimum age for Muslim girls to marry to as young as nine years old.

Amnesty International warned this month that "the amendments would also open the door to legalising unregistered marriages, which are often used to circumvent child marriage laws" and could strip "women and girls of protections regarding divorce and inheritance".

While the new amendment allows Sunni courts to issue their own code, they are still abiding by the 1959 law.