  The quantum effective action of non-minimal vector fields with Abelian or
non-Abelian gauge degrees of freedom in curved spacetime is studied. The Proca
or Yang-Mills fields are coupled to a local mass-like term acting in both
coordinate and gauge spaces. Pathologies due to gauge invariance in the
ultraviolet are avoided through the introduction of a non-Abelian version of
the Stueckelberg field. It is found that the breaking of gauge invariance
induced by the mass term affects only the tree level part of the effective
action. The ultraviolet divergent part of the effective action to one loop is
obtained using the method of covariant symbols and dimensional regularization.
Formulas are given valid for any spacetime dimension and explicit results are
shown for the two-dimensional case. As already happened for a single vector
field, the ultraviolet divergences are local but not of polynomial type.
