China outlawed sexual harassment yesterday and pledged to improve women's poor representation in politics to help make good on a national policy of equality between the sexes.

Mao Zedong famously declared that women "hold up half the sky" but in modern China they face challenges at all stages of life ranging from illegal sex-selective abortions - by couples who discover they are expecting a girl and would prefer a boy - to a preference for men in many jobs.

In a recent survey only 21 per cent of women said they had never faced sexual harassment, the official Xinhua news agency reported.

The new policies were part of an amendment to the law on the protection of women's rights, passed by the standing committee of China's Parliament, the National People's Congress (NPC).

"It is the first time we have written rules against sexual harassment into law, because it is a concern of society," Xin Chunying, deputy director of the standing committee's legal work commission, told a news conference.

She gave no details on what would be considered sexual harassment, however, saying it was hard to define clearly, and could not say what punishment there would be.

The new law also aims to expand women's presence in public life.

"The state will adopt measures to gradually enhance the ratio of women participating in the NPC as well as the local congresses," a draft of the law released by Xinhua said.