The object-oriented (OO) systems have emerged as the core systems in every field. Test case generation (TCG) for these systems has been identified as one of the crucial activity of software testing. Many researchers have been working in the area of TCG to raise the quality and effectiveness of the OO software systems. It is impossible to test the system exhaustively because of limitations of time, monetary cost and human efforts involved in the process of generation of all test cases. Presently, there is no adequate method that considers the contextual demand for the generation of test cases. Therefore, this study proposes a contextual demand-based TCG for OO systems using test paths or scenarios of sequence diagrams (SDs). Unlike the existing approaches, the proposed method considers flexible approach for generation of test cases as per the contextual demand. For the implementation of the proposed technique, two case studies, i.e. the sample SD and the SD of automated teller machine (ATM) system, have been considered. The evaluation of the proposed method showed the significant consideration of the user demand for generating the final test cases.