Chinese policymakers approved the nation's first law against domestic violence on Sunday.

The law "prohibits all forms of domestic violence" and has been hailed as a milestone in efforts to protect people from abuse in the home.

It was approved after a seven-day session of the Standing Committee of the National People's Congress, the state legislature, and will come into force on March 1.

The authority said the law defines domestic violence as physical or mental harm inflicted on someone by a family member, as well as verbal abuse.

"The most heated arguments (among lawmakers) were over the definition of 'family member' and what constitutes domestic violence," said Guo Linmao, a member of the committee's Legislative Affairs Commission. "Under current law, family members are blood relatives, people related by marriage, and those related by adoption. The general definition in Chinese law needs to be expanded."

The new domestic violence law includes an article that covers "people who live together" - for example, guardians and their charges, those living in foster families and people in cohabiting relationships, Guo said. He said that cohabiting relationships are not recognized under current Chinese law, which leaves room for judicial interpretation in many court cases.

"This new law sees us make some progress, but in a slow way," said Liu Bohong, a senior researcher with the Women's Studies Institute of China. She added, "Sexual violence has not yet been written into the law, which is a blind spot."

Deng Xiuxin, a member of the NPC Standing Committee, said the law is a good move but could be hard to put into practice. "We need to clarity the responsibilities of different departments and invest money and human resources, such as social workers," she said.

According to the All-China Women's Federation, almost 25 percent of Chinese women have experienced violence in their marriage, yet the organization said it receives only 40,000 to 50,000 complaints from women each year.

Many victims are too afraid to speak out, said Jiang Yue'e, vice-president of the China Association of Marriage and Family, which released a brochure in December to advise social workers, police and women's federation employees on how to deal with victims of domestic abuse.

luowangshu@chinadaily.com.cn