If you are referring to sweatshops, the reason why those people are paid so little is because they are not productive enough because they don't have enough skills, that's why it isn't 'slave labour', if they were more productive they would still be profitable at a higher wage level so their wages would be bid up. Also multinational companies that employ sweatshop labour often pay more than their domestic counterparts that's why these people aren't quitting their jobs, the multinationals are providing the people with the best opportunity to raise their standard of living so we should be happy that they are there. The best thing we can do for these people is to liberalise trade even further so there is more competition for labour, any attempt to raise their wages above the market level with force will lead to the costs being passed onto consumers, workers being laid off or the companies leaving altogether further diminishing the opportunity for the poor people in these countries to raise their standard of living. Redistributing wealth is also a bad idea because you are taking resources from the productive and giving them to the less productive which is inefficient, efficiency is important because efficiency means how well we make things, the better we are at making things the more stuff we can make and the more stuff that the poor people can afford to buy because as supply rises prices fall.
One of the problems with the Chinese is that they devalue their currency to encourage exports which reduces the value of the savings of the people working in the sweatshops which hurts their ability to accumulate capital.