About 70 million households require some sort of home help, but a lack of legal rights is discouraging potential newcomers.

In recent years, rising demand for domestic helpers, including nannies, has prompted hundreds of thousands of people to set up agencies.

However, most are small-scale operations and are driven almost entirely by the profit motive, meaning many do not meet industry standards. Members of staff are rarely provided with adequate training and their employment rights are hardly ever enforced.

The situation has resulted in an unstable sector where suitable or qualified workers are in short supply.

Yu Jing used to work as a sales assistant in a store in Changchun, Jilin province. The 46-year-old was made redundant, though, after her employers said she was too old to do the job. Desperate for work, she signed up with an agency in the city that supplies domestic helpers.

Though she could earn about 2,800 yuan ($414) a month, more than most unskilled jobs in her age group, Yu quit in December because the family she worked for refused to abide by the contract they had signed.

"My job was simply to do housework, but they always asked me to do extra work, like looking after their 2-year-old daughter. The parents were out nearly all the time, so I had to do both jobs," she said.

"As a newcomer, I did a lot of arduous work to gain more experience of the industry so I could earn more later on. What I could not bear was that the husband abused me by using lots of offensive language just because I asked for one day off."

According to the contract signed by Yu, the agency and the family, she was entitled to one day off per week. She hadn't had a day off for two weeks, but the first time she mentioned it, her employer shouted at her, saying, "Why don't you just quit and get out of my house?