The constructability assessment for civil projects has been considered a pivotal aspect of infrastructure project management, with significant implications for a country’s economic growth. In recent years, numerous studies have focussed on the feasibility study of civil projects and investigating key criteria related to the Constructability Review Process (CPR) to develop a practical system that enhances the decision-making capabilities of project managers and stakeholders responsible for selecting the most viable option among several alternatives. Despite considerable advancements in this field, there remains a lack of an optimised constructability assessment model that comprehensively includes all critical elements, especially within the infrastructure project life cycle. This study seeks to address this gap by proposing an optimised decision support system (DSS) for constructability assessment during the feasibility study, preliminary design, and planning stages of infrastructure projects. To complete previous constructability research in construction, the primary emphasis of this research study is on creating an integrated model based on DSS that incorporates various construction options and selection criteria. This model, developed using value engineering methodology and the Multi-criteria Decision Analysis (MCDA) approach, aims to help decision-makers choose the most suitable alternative as new options and criteria emerge. To this end, this paper delves into constructability factors and their relative importance, considering all essential criteria relevant to infrastructure construction and contributes significantly to the field by developing constructability factors tailored for large-scale infrastructure projects and introducing a decision support system using a hybrid MCDA method as a valuable tool for assessing constructability. An existing old bridge in Australia has been used as a case study to provide a concrete example and evidence of how to apply the proposed hybrid Multi-criteria Decision Analysis (MCDA) tool. This system empowers designers and decision-makers to make project decisions based on specific criteria and constraints, enhancing overall project outcomes.