Best do nothing
They shouldn't aim for a minimum wage. All it will do is depress wages as bureaucracy will never be quick to increase it. If there is no minimum wage, but there are lots of jobs, then just the demand for workers will cause the companies to increase wages to keep their staff.
As for $220/month. It might not be a living wage in Singapore itself, but in Bantam it probably goes a long way for those living in the shacks on stilts. Context is everything. It's like the calls for a national minimum wage here in the UK which then has to have exceptions for London. Even inside a small country like the UK the cost of living depends on where you live. Demands for the Living Wage have caused the public sector in the North East to be a lot better off than the private sector, and the private sector cannot afford the NMW for those whose jobs aren't worth it. They'd rather overload existing staff than get another person in (along with Employers NI and other costs).
Bantam is the current location for cheap labour, just like Japan was, then China. Now Chinese wages increase by over 20% each year, so they are looking for cheap labour themselves. Bantam and Africa are the place the Chinese are looking at.
So the wages of those in Bantam are low. Now. For a short time. But given the increase in workers, and the demand for them, it won't be long before their wages increase. So rather than worry about it and think like all politicians that "something must be done", the best thing is to do nothing and let the workers go to the jobs which pay better and have better conditions. Simple market forces will cause wages to increase within a few years.