In the present work, a high order implicit technique is associated with a meshless method to model material mixing observed in friction stir welding (FSW) process. This new algorithm combines the following mathematical procedures: a time discretization, a space discretization, a homotopy transformation, a perturbation technique and a continuation method. The perturbation technique, after a time discretization, a space discretization, a homotopy transformation, transforms the nonlinear problem into a sequence of linear ones at each time. By comparison to the classical iterative algorithms, the proposed one allows obtaining very large time steps and reducing computation time by minimizing the number of tangent matrix decompositions. The strong formulation is considered to avoid the drawback of numerical integration. The resulting algorithm is well adapted to large deformations in the mixing zone nearly the welding tool. We limit ourselves to bidimensional visco-plastic problems to show the performance of the proposed algorithm by comparison to the classical incremental iterative methods.