In the field of software engineering, it is now recognized that proper language design can greatly improve the reliability, clarity, ease of implementation and maintenance of software written in that language. Two valuable features of languages designed for the implementation of reliable software are 'strong typing' and structured control statements (e.g. if-then-else and while-do). Basically, 'strong typing' means that every variable must be declared to be of a specific type before it is used, and only expressions of that type may be used to assign new values to the variable. However, despite evidence that shows the usefulness of strongly-typed languages, most simulation languages do not have this feature. At present, the best known simulation language with strong-typing is SIMULA and it is implemented on only a few machines since a SIMULA compiler is relatively complex and expensive to implement. SIMPAS is another strongly-typed simulation language developed at the University of Wisconsin in early 1981. Like many other new simulation language, it is not widely known and used at present, mainly because users are generally reluctant to learn a new language Just for the purpose of writing a simulation. The easiest way to introduce new software features into the user community is via the implementation of a suitably modified (with regard to data declarations and control flow structuring facilities) subset of a widely used simulation language. Such a language would be more readily accepted by the user community, especially among the users of the original language because those users will not be required to learn a completely new language. This report introduces and discusses the design and implementation of a modified subset of the widely used General Purpose Simulation System (GPSS) on the PRIME/750 computer system at the University of Canterbury computer centre. It is assumed that the reader is familiar with the basic concepts of discrete event simulation systems.