A proposed method (M.J. Dutch et al. 1986) for driving steady poloidal and toroidal currents in a tokamak by means of RF currents in double sets of m=1 helical coils is investigated using a simple theoretical model. Numerical results are presented that show a strong dependence of the current drive mechanism on the strength of the static toroidal magnetic field. Contrary to previously published theoretical results, it is shown that in general the driven toroidal current does not vanish at some point close to the magnetic axis.