KABUL (Reuters) - A new law for Shi'ite Muslims in Afghanistan has provoked anger among some lawmakers and the United States and United Nations said they were concerned about its impact on women's rights in the former Taliban state.

The law passed by parliament and signed by President Hamid Karzai, but not yet promulgated in the official gazette, is meant to legalize minority Shi'ite family law, which is different from that of the majority Sunni population.

Shi'ite Muslims make up about 15 percent of the population.

The U.N.'s agency for women, UNIFEM, said in a statement it had yet to study the final draft of the Shi'ite Personal Status Law, but said it "remains seriously concerned about the potential impact of this law on the women of Afghanistan."

A copy of the bill obtained by Reuters shows many of the articles which had initially angered lawmakers, such as the age of marriage for women and the age at which children can stay in their mother's custody after a divorce, have changed.

The age of marriage for women has been raised to 16 from nine and the age at which a mother can keep custody of her daughter after a divorce was raised to nine from seven.

But Shinkai Karokhail, a woman parliament member, said the law would take women's rights backwards in Afghanistan: "I cannot support this law, personally I really feel hurt ... it will really increase brutality in our lives."

One Afghan woman official, who is also Shi'ite, said many changes had to be made to the law before it was promulgated.

"Parliament has not been able to debate the law properly and draft it properly. They have really rushed it through, without letting parliamentarians properly discuss it," said Azra Jafari, a mayor in central Dai Kundi province.

Deeply conservative

One of the most problematic articles, Jafari said, stated that a man could demand sex from his wife at anytime.

"I hope this law will be revised again ... I really hope it is not implemented in the shape that it is in now," Jafari said.

Jafari said in principle the law was important and needed for Afghanistan's Shi'ite community after years of persecution, particularly under the Taliban.

"But this law needs more consideration and debate. Lawyers, intellectuals and religious scholars -- these people should have sat together and debated this law," Jafari said.

Sayeh Hussain Alemi Balkhi, a lawmaker involved in debating the bill in parliament, dismissed British media reports that it legalized marital rape and prohibited women leaving home without their husband's permission as "propaganda."

Women's rights have improved significantly in Afghanistan since the 2001 overthrow of the strict Sunni Islamist Taliban government. It prohibited women from working, attending school or leaving their homes without a male relative.

But Afghanistan remains a deeply conservative Muslim society, particularly in remote rural areas, something the Kabul government has to balance alongside demands from its Western backers for a pluralistic, democratic political system.

Jafari and Karokhail said Karzai's approval of the law was a move to gain favor with the Shi'ite electorate before an August 20 election.

"Karzai just signed it so as not to cause any problems," Karokhail said.