My Masters was in Applied Anthropology and Participatory Development and, like you, I fell comfortably into the translation industry. As far as I know, NGOs in my language pair tend to rely on those working in their industry rather than hiring us pros for translation and if they were to hire us, their budget would only be a fraction of what you'd expect. If you do find a tip or strategy, please do share! Meanwhile it's clinical trials and banking docs for me!
That's been my experience too so far, although the one job I've gotten directly from an NGO so far actually paid really well, compared to my agency rates at least. The problem is just finding NGOs that are willing to pay at all, but some well-known translators (Corinne McKay for instance) don't appear to struggle with that.
And yeah, I'm translating tourism brochures and an IT company's website this weekend - riveting stuff.
...and try to work with government agencies involved in international development, human rights and so on? You could start by looking for translation agencies that do a lot of work for the government and you could also inquire directly about how to get qualified to work for local / federal / international government bodies --but of course, it's not easy, as tons of people want those jobs.
Good tip! For some reason I hadn't considered that. The more I think about it, Denmark has a lot of agencies involved in that kind of stuff that I haven't put on my prospects list.