A range of stress‐based plasticity criteria have been employed in the finite element analysis of the post‐elastic behaviour of bone. There is some recognition now that strain‐based criteria are more suitable for this material because they better represent its behaviour. Moreover, because bone yields at relatively isotropic strains, a strain‐based criterion requires fewer material parameters unlike those required for a stress‐based criterion. Based on a minimum and maximum principal strain criterion, a robust strain‐based plasticity algorithm is developed. As the criterion comprises six piecewise linear surfaces in principal strain space, it has a number of singular regions. Singularity indicators are developed to direct the algorithm to make appropriate plastic corrector returns when singularity regions are encountered. The developed algorithms permit a plastic corrector to be achieved in a single iterative step in all cases. A range of benchmark tests are developed and conducted after implementing the algorithm in a finite element package. These tests show that the constitutive behaviour is as expected. Copyright © 2012 John Wiley & Sons, Ltd.