The group, led by confederation chairman Alan Crane and president Sir Martin Laing, held talks with Alan Donnelly, leader of the Labour Party in Brussels, and Emilio Gabaglio, head of the European Trae Union Congress.
Confederation European director John Bromley said the aim of the mission was to ensure that contractors' views were not overlooked when legislation was drafted.
Bromley said: "Between 70% and 80% of all UK legislation emanates from Brussels, and we need to be able to influence how it is drafted at an early stage."
Bromley described Gabaglio as a key player in the drafting of European social legislation and said it was important that the confederation got its views across to the ETUC.
The confederation is to open a permanent office in Brussels.