The UN isn't a global police force. All it can do its organise sanctions to force the PNG government to do something about it or get nations to contribute to some sort of fund to improve education and policing domestically.
Nor should it be a global police force. I think people/countries that don't condone this type of behavior should be more willing to offer refugee status and provide the means to leave such places and situations, but people are pretty hard-mouthed about their borders... At the end of the day, we can't tell people what to do, only offer them alternatives.
