The behaviour of low-frequency drift waves in a two-species plasma under the influence of a large-amplitude spatially uniform electric field oscillating at the ion-ion hybrid frequency and applied across an ambient static magnetic field has been studied. The threshold powers for the parametric excitation of these drift waves are calculated and the characteristics of the dispersion relation near threshold and well above threshold are examined. At large applied powers (much above threshold), interesting modifications of the natural drift modes are found.