We investigate symmetries of the scalar field theory with harmonic term on
the Moyal space with euclidean scalar product and general symplectic form. The
classical action is invariant under the orthogonal group if this group acts
also on the symplectic structure. We find that the invariance under the
orthogonal group can be restored also at the quantum level by restricting the
symplectic structures to a particular orbit.Comment: 12 pages, revised versio