The aim of this note is to examine the effect of imperfect monitoring on bribery and corrupt practices in public administration. Our findings suggest that if we would reconstruct public service system to exterminate its bribery and corrupt practices, the rate of turnover of the bureaucrat and the amount of the noise in monitoring its behavior should be in the suitable regions respectively. We introduce imperfectness of monitoring the behaviour of the bureaucrat into the infinitely repeated game model developed by Balafoutas (2011). Supposing that the players adopt strategies with two-phases, the corruption and punishment phase, we derive the extent of the amount of the bribe for the bureaucrat and the lobby to sustain collusion in the corruption phase. Moreover, we show a sufficient condition for the two-phase strategies to constitute a psychological Nash equilibrium
