It's an open secret that Singapore rely heavily on cheap labors from overseas for many jobs that Singaporeans are refusing to do: construction works, live in maids, hawker centers cleaning (some old Singaporeans do do this though).
In many household it's common to have 1, or in some of my friends' home, 2 live in maids to help with chore. They get paid around 400-600 SGD (250-400 USD) per month depends on where they are from, how fluent they are in English and are expected to work at least 5 days a week. The employer keeps their passports, and can pretty much send the maid back to their country immediately. This imbalance relationship feels very wrong to me, but most people here don't care.
Because the pay is low, the quality and ethic of some domestic helpers are not great. Some do steal and sabotage their employers when they're not happy, I've heard many horror stories over the year. On the other hand, many employers don't see them as equal, or even human. A quick google will show you both side of the story, and for all the good things Singapore have to offer, low-pay workers' right is virtually non-existent and as long as Singapore benefit from it, I don't think it will change anytime soon.
Edit: Something I forgot to include: employers do provide a room and meals for the maids, so their expenses in Singapore is minimal if they want to, and in many cases they send most of their salary back home.