The application of law is based not only on the legal text but also on some guidelines concerning its interpretation. This can lead to considerably different understanding of provisions of law which reduces legal certainty and social trust in judiciary. Legal provisions concerning statutory interpretation may increase the uniformity of judicial practice and thus citizen's trust in the state. On the other hand they can become a tool of pressure and manipulation and thus increase a distrust and dissent. This paper consists in the analysis of potential dangers related to the creation of interpretative regulations by the legislator. I will refer to the existing controversial interpretative provisions I will look for criteria for the legality of such regulations. The goal is to indicate the boundaries as to the content of statutory interpretative directives so that they do not violate the separation of powers and judicial independence.