Public housing projects (PHPs) in New Zealand are with cost cap. Cost estimate at the pre-tender stage could determine whether a project to be dropped or continued. This study explored the current practices and shortfalls in improving the accuracy of PHPs cost estimate by undertaking an exploratory study using combination of literature review and semi-structured interviews with cost estimators within New Zealand. Even though there was no argument of the importance of improving PHPs cost estimate accuracy level, the current practice in New Zealand context does not consider (1) factors other than inflation; (2) features of each design stage and the key factors work at each design stage. The knowledge gained from this study could help cost estimators and key stakeholders to be aware of the current circumstance, existing practices and the gaps of existing practice of improving the accuracy of PHPs cost estimates, thus contribute to achieve the project success.