This paper builds a system dynamics model to study the impact of some activities of public corruption on economic growth. The model is articulated around a generic economy in which a public and a private sector take part. The sectors produce different goods using the same available economic resources. Both use labour and could employ different criteria for remunerating their workers. The difference between the private and public wage allows the model to justify the introduction and the persistence over time of public corrupt activities in the economy. The causal structure collects the decisions and the rules of behaviour of the economic agents. It reflects the normal economic activities and the interactions between them and the new causal relationships arising from the corruption activities. The feedback processes totally explains why corruption modifies both the public and private production as well as the wealth of some citizens. After formulating the decision rules of the economic agents, calibrating the values of the parameters and the initial conditions of the levels, a simulation exercise is carried out to characterize the growth attained by the economy under different scenarios taking into account different degrees of corruption and different ways for fighting against it.