A plethora of regulatory environmental planning policies constrain on-site construction operations, to theoretically minimise negative environmental impact and create sustainable practice. However, it is widely acknowledged that the construction sector continues to remain a significant cause of environmental degradation, even in contexts where policies and regulations exist. In this manner, a disparity exists between policy intent and policy outcome. The purpose of this study is to explore how policy implementation may influence the disparity between policy intent and policy outcome in the context of regulatory environmental planning policy and on-site construction environmental management operations. Importantly, the study moves beyond State authorities responsible for, inter alia, policy formulation and ratification, as it concentrates upon policy users: ground level implementation actors (government and non-government) and activities. Understanding key issues associated with policy implementation from the literature, a two-stage qualitative research design was adopted to explore policy implementation. In addition to key issues with policy implementation identified in the literature, the findings identified four context-specific conditions that impact upon successful implementation: policy operationalisation, organisational position, professional belief, and specialist knowledge and understanding. The implications demonstrate cultural change across the sector as fundamental for successful policy outcomes, and ultimately, environmental protection.