We analyze a two-dimensional SU(3) gauge model of Wilson lines as a dimensionally reduced model of high temperature QCD 3 . In contrast to perturbative dimensional reduction it has an explicit global Z3 symmetry in the action. The phase diagram of the model is studied in the space of two free parameters used to describe the self interaction of the Wilson lines. In addition to the confinement–deconfinement transition, the model also exhibits a new Z3-breaking phase. These findings are obtained by numerical simulations, and supported by a perturbative calculation to one loop. A screening mass from Polyakov loop correlations is calculated numerically. It matches the known QCD 3 mass in a domain of parameters belonging to the normal deconfined phase.