A hybrid electrical power assist system (EPAS) for an automotive vehicle that utilizes the advantages of a conventional EPAS system to provide power assist based upon several distinct sensor inputs, in a heavy duty vehicle that requires significantly more assistance forces than a conventional EPAS can provide. The hybrid system utilizes a hydraulic amplifier that is connected to receive the torque output from an EPAS motor actuator and responsively provide a fluid under differential pressure through a pair of high pressure lines to a steering piston.