Within the effective-mass approximation, we investigate the electronic structure of hexagonal quantum-disc clustersusing the finite element method. With an increasing amount of quantum dots in the cluster, the electronic energy levelsquickly expand into mini-bands, each consisting of discrete, unevenly distributed energy levels. The correspondingelectronic eigenfunctions are linear combinations of the electron orbits in each quantum dot. The spatial symmetry ofthe combination is the same as the electronic eigenfunction of a single quantum dot.