Results from a theoretical model of long wave generation by a time varying break point over a linear shore parallel bars are presented. Standing wave solutions between the shoreline and the mean break point over the bar are obtained, and two possible resonance conditions are identified. First, a quarter wave resonance condition is defined, having a node in the sea surface elevation at the forcing over the bar. Second, a half wave resonance occurs when the surface elevation has an antinode at the bar crest. The model results predict a resonant response corresponding to the half wave resonance but a quarter wave resonance is not seen, the response being limited by an outgoing energy flux in the form of a seaward propagating progressive wave. The occurrence of an elevation antinode at the bar crest leads to the possiblity of convergence in suspended load at this point and hence to a possible mechanism for the maintenence of the bar. At resonance the constructive modes, those tending to maintain the bar, are amplified, while the destructive modes, those tending to create a trough at the bar position, are actually suppressed by the topography.