[en] In the absence of a Higgs particle vector boson scattering amplitudes are generally described by an electroweak chiral Lagrangian below the resonance region. For a linear collider with CMS energy √(s)=1.6 TeV and an integrated luminosity of 200 fb^-1 we estimate the sensitivity on the chiral parameters α₄ and α₅. We consider the processes e⁺e_-→W⁺W^-anti νν and e⁺e^-→ZZ anti νν, performing a complete calculation which includes all relevant Feynman diagrams at tree level, without relying on the equivalence theorem or the effective W approximation. The dominant backgrounds and W/Z misidentification probabilities are accounted for. (orig.)