Construction managers have for a long time focused their attention on conversion processes, with little attention given to flow activities, leading to uncertain flow processes, expansion of non value-adding activities, and reduction of output value. This paper investigates the incidence of non value-adding activities in construction projects in Indonesia and Australia, focusing on non-residential building and infrastructure projects. Data was collected via questionnaires and personal interviews targeting 99 respondents from Indonesia and 50 respondents from Australia. A quantitative approach was adopted for this research utilising the results of a questionnaire survey involving 53 variables that relate to non value-adding activities. The variables were then separated into two classifications: waste categories that contribute to a reduction in the value of construction productivity and waste cause variables that could be defined as factors producing waste. Statistical analysis was performed to identify the different perceptions amongst the respondents and to determine the key variables of non value-adding activities. The paper illustrates the key waste categories, the key waste cause variables and leads the contractors to focus their attentions on these issues in order to reduce the incidence of non value-adding activities during the construction process