This paper adopts a model-based security (MBS) approach to identify security requirements during the early stages of multi-agent system development. Our adopted MBS approch is underpinned by a meta-model independent of any specific methodology. It allows for security considerations to be embedded within any situated agent methodology which then prescribes security considerations within its work products. Using a standard model-driven engineering (MDE) approach, these work products are initially constructed as high abstraction models and then transformed into more precise models until code-secific models can be produced. A multi-agent system case study is used to illustrate the applicability of the proposed security-aware metamodel.