A plasma-based opening switch, capable of handling kiloampere currents at kilovolt potentials on the microsecond timescale, is described and characterized. The principle of operation is the deflection of a laser-induced arc by an external magnetic field to a shunt circuit path. A first-order model of operation is introduced. Finally, the merits of the device, particularly when applied to high-repetition-rate dense plasma focus (DPF) systems, are discussed.