The scattering of focused laser beams by arbitrarily shaped dielectric bodies is investigated theoretically. The beam description is based on Davis third-order beam approximation for the field components. The scattering problem can be solved on a spherical basis by the extended boundary condition method or by the so-called modified version of the extended condition method. For spheroidal particles with small eccentricities, a perturbation technique for the internal subproblem of the extended boundary condition method is described. This procedure is applied to analyse the influence of the particle shape and orientation on the response of a phase-Doppler system.