This paper deals with the blocks relocation problem (also called container relocation problem). First, it corrects the binary linear programming model BRP-II presented in Caserta et al. (2012). Second, it improves the initial model formulation by removing superfluous variables, tightening some constraints, introducing a new upper bound and applying a pre-processing step to fix several variables. Computational results show the efficiency of the improved model for small and medium sized instances.