Smoothed particle hydrodynamics (SPH) is a meshlesss Lagrangian particle method. It is suitable for numerical analysis of structural components involving complex geometrically nonlinear constitutive equations; both fluid-like and solid-like types of behaviour can be simulated. The current study focuses on techniques allowing for increased accuracy of computations of elasto-viscoplastic problems at finite strains. Apart from the use of corrected weighting kernels, an accurate computation of reaction forces is discussed. As a benchmark, inhomogeneous tension of plates under plane strain and plane stress conditions is considered. The mechanical response is defined by hyperelastic and visco-elastoplastic relations. Converged numerical results obtained by the finite element method (FEM) are considered as a reference solution. Linear convergence of the SPH procedure to the reference solution is detected. It is shown that by application of refined methods a suitable accuracy can be achieved using a relatively small number of particles.