Systems Engineering (SE) is an approach for designing complex systems in a multidisciplinary universe, based on concepts from the systemic paradigm and promoting languages, methods, and standardized processes. Requirements engineering is one of the main steps in SE processes. The current research presented in this paper aims at focusing on the open issue related to the formalization of systems requirements for their verification, ensuring the coherence of the whole set of requirements in each contextual engineering domain and their validation against the initial stakeholders' needs. Moreover, requirements coming from different domains are generally linked by non-formalised traceability relationships. It is even difficult to trace any change in their definition and their impact to the whole set of specifications. The paper discusses and proposes an approach for systems requirements engineering based on a rule and notification oriented approach for ensuring the effective coherence and understanding of these requirements throughout the life cycle of any complex system. This proposed notification approach is derived from the so-called Notification Oriented Paradigm (NOP), a new rule and event driven approach for software and hardware specification and execution.