The concept of new Gauss-Seidel like iterative methods, which was introduced in [3], will be extended so as to obtain a class of convergent Gauss-Seidel like block iterative methods to solve linear matrix equations Ax = b with an M-Matrix A. New block iterative methods will be applied to finite difference approximations of the Laplace's equation on a square ("model problem" [a]) which surpass even the block successive overrelaxation iterative method with optimum relaxation factor in this example.