Purpose – In e-government domain, an efficient semantic interoperability of services is a big challenge. In this context, semantic technologies play a fundamental role in numerous e-government programs. Indeed, these technologies enable enriching the public service description provided by different public administrations with additional semantic information, which allows automatic services processing and information exchange between involved members in comprehensive and interpretable manner, thus facilitating service integration and cooperation. The most frequently used technologies in this area are semantic web services (SWS) technology and ontology. Thus, for modelling efficiently public services, the authors have exploring, studying and analyzing some of e-government researches and projects that applied semantic technologies. Design/methodology/approach – In this paper, the authors address how semantic technologies transform the e-government domain through exploring and studying the use of SWS and ontology in numerous researches and projects applying these technologies in this area. Then, the authors have compared them through a set of criteria defined according to e-government requirements such as the SWS modelling approach for describing semantically public services, ontologies for representing governmental specific features (e.g. regulation and organizational structures) and developed portal for supporting user ' s perspectives. Based on this study, the authors have identified the appropriate standards, frameworks, and models for developing the framework. Findings – The authors have developed a framework for public services which enhances existing approaches with additional aspects. Thus, the approach comparing to other works improves the service ontology with a cognitive semantic approach to support the multiple usage contexts and situations of services. This semantic is developed in form of a Sit/Ctx ontology developed based on CSs model represented through conceptual graphs theory. The authors have used this model besides OWL-S, improving thus the level of automation of discovery and composition process of public services, which become more efficient with taken into consideration their interrelations and situations. Originality/value – The approach comparing to other works improves the service ontology with a cognitive semantic approach to support the multiple usage contexts and situations of public services, providing thus the end-users (people and enterprises) a better orientation in discovery process.