As part of performing regular management tasks that are performed in the operations of numerous and different companies, i.e. legal entities, it is necessary to connect various supports in order to achieve essential reality. The aim of the paper was to determine the connection between the work of internal audit and IT support systems in the work of the public sector of the Republic of Serbia in relation to the classic business of the public sector. This was achieved by conducting a targeted survey of the aforementioned subjects and analysing the influence of four factors: monitoring costs, monitoring revenues, cost dynamics and revenue dynamics. The results obtained indicate that there are significant differences in the application of the aforementioned two behavioural models in the public sector because the obtained values ​​are significant for all the aforementioned factors (p<0.0005*). However, we obtained the highest value for the cost dynamics factor, where the t value was the highest and amounted to -10.034, according to top managers. This implies that in the coming period, special attention should be paid to public sector operations with systematic monitoring of cost dynamics as a key factor for the success of the aforementioned two forms of public sector operations. Such model action is important for future business because it links cooperation between IT and internal auditor reporting to ensure the security and truthfulness of public sector reporting, which has been done using the example of the economy in the Republic of Serbia.