In the framework of the osp(1, 2)-symmetric quantization of irreducible massive gauge theories the background field method is studied for the simplest case of a linear splitting of the gauge field into a background configuration A i and the quantum fluctuations Q i . The entire set of symmetries of that approach, including three types of background-dependent gauge transformations, is expressed by the corresponding set of Ward identities. Making use of these identities, together with the equation of motion of the auxiliary field, the background dependence of the generating functionals of the 1PI vertex functions and the Green's functions is completely determined by the dependence of these functionals upon the gauge fields and the associated antifields. It is proven that the introduction of a background field does not change the ultraviolet asymptotics of the theory. *