This paper presents the features of a recently developed ground surface contamination monitor based on wide area plastic scintillation detector and investigates the design and performance characteristics of the system. The system incorporates an innovative methodology for suppressing the general background radiation influence on the detector response. The methodology involves the incorporation of a suitably positioned gamma sensitive Geiger Muller tube, the output of which is used to compensate for the general background interference in the response from the plastic scintillation detector. This paper reports on the performance evaluation of the system and the parameters considered for setting the alarm levels.