The molecular mechanisms by which IAV replicates and transcribes its genome segments have generally been well studied. However, the way by which IAV regulates and balances the replication/transcription of its 8 genome segments is much less understood. In order to study and manipulate these processes, we developed a dual reporter genome segment assay that enabled us to analyze whether the replication/transcription of one genome segment is affected by that of another. Our results indicate that this is indeed the case as luciferase expression driven from a reporter genome segment was shown to be affected by the presence of other genome segments, both in the context of virus infection and in the presence of polymerase and NP proteins provided by transfection of the expression plasmids. Furthermore, our results indicate that genome segments are likely to compete with each other for the available viral proteins and that the balance between different genome segments is affected by reporter genome segment length, by the identity of 39 and 59 UTRs, and probably also by their coding regions.