1/ @hrw has released its world report on the human rights situation in every country. For Singapore, here is what it says about migrant workers
2/ Foreign migrant workers are subject to labor rights abuses and exploitation through debts owed to recruitment agents, non-payment of wages, restrictions on movement, confiscation of passports, and sometimes physical and sexual abuse.
3/ Foreign women employed as domestic workers are particularly vulnerable to abuse. Foreign domestic workers are still excluded from the Employment Act and from many key labor protections, such as limits on daily work hours and mandatory days off.
4/Work permits of migrant workers in Singapore are tied to a particular employer, leaving them extremely vulnerable to exploitation. Labor laws also bar them from organizing and registering a union or serving as union leaders without explicit government permission.
More information here