[Arran]

If the areas where the finish is missing are clean, and the rest of the lacquer seems to be firmly adhered, you could try touching up the bare spots with brushing lacquer, depending on how much is missing. You can basically using brushing lacquer to fill in the deficits in the original finish, then you follow that with fine sandpaper to level everything out, then you spray lacquer over top and hope it sticks. However it's been my experience that when the finish gets worn off in a large ring around the knobs (for example), that dirt and oil often gets worked into the grain from someone's fingers and the area becomes discolored or stained up, sometimes you can remove it and sometimes you can't without stripping the cabinet and sanding it off.
Without being able to see what the missing areas look like, or how large they are, it's hard to judge whether the original finish is worth the effort of saving. As I mentioned before on such a small cabinet it doesn't take that long to completely strip, fill, seal, and lacquer it again, if more then maybe 5%-10% of the finish has worn off or flaked away it would take more effort to save whats there then to just start over.
Regards
Arran