From the turn of the century onwards, the traffic in women and girls between southern China and Malaya included the importation of young girls for the purpose of domestic servitude as mui tsai.

The mui tsai system reflected the position of poor women within the Chinese social structure. In times of economic hardship, young girls were sold or transferred as mui tsai for domestic servicing in return for food and shelter. When a mui tsai grew up, she was either married off to a man usually of her employer's choice or remained in domestic servitude in the household. She could also be a san po chai (little daughter-in- law) betrothed to a son of the household as his future wife or concubine. Until she reached a suitable age for marriage, her labour power could, in the meantime, be utilized in domestic servicing and other work.

In Malaya, the mui tsai system is to be seen in the context of the shortage of adult women for reproductive servicing, particularly in wealthly Chinese households, and the conditions of poverty in China and Malaya. Some households hired male domestic servants based on a regular wage system but this was a relatively new and unfamiliar system. Hired male domestic labour was more expensive because fixed wages had to be paid and conditions of work negotiated with the male servants who were organized in secret societies or groups and thus were in a position to bargain with the employers. It also lacked some of the advantages gained from traditional forms of female domestic servitude, particularly those services required by female members of the household as well as the possibility of the mui tsai becoming a wife or concubine of a male member of the household. In contrast, the conditions for control by employers were greater under the traditional mui tsai system and the demand for domestic labour thus largely fell upon this system.