This paper (Italian version) gives the first empirical results of an ongoing research on the dynamics of the European port labour in comparative perspective. Starting from the analysis of the documentation obtained through the use of qualitative methods in the port of Genoa, the article focuses on the relationship between the role of the actors who control large segments of the supply chains and their ability to shape the structure of the port labour. The proven strategies of the major market players, in the pursuit of economies of scale in the context of global supply chains, produce pressure on the port of Genoa, which would alter not only the technical configuration of the terminal, but the functioning of the labor pool itself, constrained in the use of external resources. The flexibility processes generated by the merger of trade sanction a shift that calls into question the role of institutional constraints with respect to the port performance and the European port labor systems. In the light of a comparison with the port of Antwerp, this paper provides a recognition of the theoretical framework necessary to interpret the behaviour of port actors and to assess the existence of beneficial constraints both for port actors and for the contractual system of port labour.