  The deconfinement phase transition in large-$N_c$ QCD is studied within the
framework of an effective Polyakov-loop model, where the potential has a U(1)
symmetry originating in the large-$N_c$ limit of a Z$_{N_c}$-symmetric model.
At the critical temperature, the shape of the effective potential allows the
existence of Q-balls as position-dependent fluctuations of the Polyakov loop.
Q-balls with spherical or axial symmetry are numerically obtained from the
equations of motion of the effective model under consideration. The physical
properties of these non-topological solitons (mass, charge and size) are
discussed, as well as their interpretation in terms of spinning "bubbles", with
various shapes, of deconfined matter surrounded by a confined environment.
