For structural components made of sintered metals the porosity may be rather high, and this affects conditions for material failure. A simple model for analysis of shear band development in uniformly strained solids is used here to study the effect-of rather high initial porosities on the onset of a material instability. The elastic plastic behaviour of the material is represented by a material model, which combines the Gurson model, relevant to rather low porosities, with the FKM model, developed for high porosity powder compacts. Predictions are shown for various levels of initial porosity and for various levels of initial material:imperfections, considering both plane strain and axisymmetric conditions outside the shear band. Also a comparison of localization predictions by the Gurson model, the FKM model and the combined model is presented. (C) 1999 Elsevier Science Ltd. All rights reserved.