Ductile matrix failure in a metal reinforced by short parallel fibres is studied numerically in terms of full three-dimensional cell model analyses. The model is extended here, relative to the simplest possible cell, such that transversely staggered fibres are accounted for and such that effects of different sizes of two neighbouring fibres can be studied. The matrix material is described in terms of a porous ductile material model, which accounts for the nucleation and growth of voids to coalescence. Most predictions are based on an isotropic hardening model, but results for kinematic hardening are used to study the effect of a metal that forms a rounded vertex on the yield surface. The damage evolution tends to first show the formation of an open crack near the ends of the longer fibres, by void coalescence in the matrix, and subsequently a similar crack evolves near the ends of the shorter fibres.