The sustainment of a reversed field pinch using electrostatic helicity injection in conjunction with the usually applied axial electric field is investigated. Non-linear magnetohydrodynamic simulations indicate that it may be possible to sustain the plasma in a resistive steady state free from current driven modes and the associated dynamo relaxation. Moreover, the core region is well confined by nested flux surfaces. Practical considerations such as the impedance and efficiency of the injection circuit are discussed.