Abstract Background In Belgium, the management of sick leave involves general practitioners (GPs), occupational health physicians (OPs) and social insurance physicians (SIPs). A dysfunctional relationship among these physicians can impede a patient’s ability to return to work. The objective of this study was to identify ways to improve these physicians’ mutual collaboration. Methods Two consensus techniques were successively performed among the three professional groups. Eight nominal groups (NGs) gathered 74 field practitioners, and a two-round Delphi process involved 32 stakeholders. Results From the results, it appears that two areas (reciprocal knowledge and evolution of the legal and regulatory framework) are objects of consensus among the three medical group that were surveyed. Information transfer, particularly electronic transfer, was stressed as an important way to improve. The consensual proposals regarding interdisciplinary collaboration indicate specific and practical changes to be implemented when professionals are managing workers who are on sick leave. The collaboration process appeared to be currently more problematic, but the participants correctly identified the need for common training. Conclusions The three physician groups all agree regarding several inter-physician collaboration proposals. The study also revealed a latent conflict situation among the analysed professionals that can arise from a lack of mutual recognition. Practical changes or improvements must be included in an extended framework that involves the different determinants of interdisciplinary collaboration that are shown by theoretical models. Collaboration is a product of the actions and behaviours of various partners, which requires reciprocal knowledge and trust; collaboration also implies political and economic structures that are led by public health authorities.