Theories of efficiency preorders and precongruences for concurrent systems have been described in various papers. We describe a procedure to implement two of these precongruences. Considering the extra information that is needed to be maintained while computing efficiency preorders, our procedure with a complexity $O(n^{3}m)$, compares favourably with that for deciding observational equivalence ($O(n^{\alpha }m)$. Further, the algorithm may be plugged in to existing model-checkers such as the Concurrency-Workbench of the New Century (CWB-NC) without any significant overheads of space or time.