You meant figurative, but I think I'm going to steal illiteral from you. :D It's nice to have polar opposites when explaining things. ^^
I'm guessing "it's dirty work" would be something like "det är smutsig arbeten". Because of the article ett, the translation requires "a job". I would not say "a work" in English unless talking about a created object, like a work of art.
As a native Swede I would actually say "it's dirty work" is an acceptable translation for the sentence, even if I would recommend one closer to the original to be on the safe side.