Purpose: This study aims to investigate Information Systems (IS) project risks in the South African public sector, and to develop a systemic model of the most dominant risks encountered and identify the interrelationships that exist between these risks. Design and methodology: The study is conducted through the application of Interactive Management (IM) to identify IS project risks and structure the interrelationships between them. The IM methodology comprises of four key phases: Idea Generation, Idea Clarification, Idea Structuring, and Interpretation. A workshop with a group of participants is required to carry out an IM intervention successfully. During the Idea Generation phase, participants are asked a triggering question to elicit ideas, which are then clarified and structured in the subsequent phases of IM before final interpretation. Findings: In the Idea Generation phase, six IM participants working on public sector IS projects were asked a triggering question to elicit dominant IS project risks they perceive to be important. The participants initially identified 34 IS project risks, which were reduced to 24 after they brainstormed their relevance during the Idea Clarification phase. Further deliberations led to the participants removing another risk during the Idea Structuring phase. During the Idea Structuring phase, the remaining 23 risks were structured to produce an Interpretive Structural Modelling (ISM) digraph with the aid of software. The ISM digraph revealed three risk factors as the primary drivers of IS project risks in the public sector, specifically, in the context of this study. These risks are ‘lack of consultation with users', ‘budget cuts' and ‘excessive red tape'. Value of study: This research contributes to the following: (1) the existing knowledge-base on public sector IS project risk management; (2) the focus on a soft systemic approach such as IM helps in uncovering context-specific issues on IS project risks that may not be available in extant literature; and (3) the collaborative learning process of the IM approach adds to research on the sustainability of complex IS projects implemented in the public sector.