PurposeThe leadership style and communication practices of supervisors in the Australian construction industry were measured. The purpose of this paper is to investigate the effect of leadership style and communication practices of Australian construction supervisors on workgroup health and safety (H&S) climate and behaviour.Design/methodology/approachA questionnaire was administered to members of 20 workgroups engaged in rail construction work on the Level Crossing Removal Project and the Melbourne Metro Tunnel Project in Victoria, Australia. The survey measured components of supervisors’ transformational and transactional leadership, communication practices, the group H&S climate and workers’ self-reported H&S compliance and participation.FindingsSupervisors’ transformational and transactional leadership, as well as communication practices, were all positively and significantly correlated with group H&S climate and workers’ self-reported H&S behaviours. The transformational leadership component of providing an appropriate model was the strongest predictor of H&S participation, while H&S compliance was predicted by the transactional leadership component of providing contingent reward, as well as supervisors’ communication practices. H&S climate fully mediated the relationship between supervisory leadership and workers’ self-reported H&S behaviour.Originality/valueThe research demonstrates that both transformational and transactional supervisory leadership are important in the construction context. Effective communication between supervisors and workers is also important for H&S. The findings suggest that supervisory leadership development programmes may be an effective way to improve H&S performance in predominantly subcontracted construction workgroups.