[en] Since the discovery of the first exoplanet around 51 Pegasi, the study of planetary systems receives an increasing attention, with the development and test of more and more detection techniques. Among the direct detection techniques, interferometry is one of the most promising for the near future. It already provides the required angular resolution, but the dynamic range needs to be improved. The detection and characterisation of extrasolar planets is one of the main science cases of the 2nd generation VLTI Spectro-Imager instrument (VSI). The goal of this work is to study the feasibility of obtaining near-infrared spectra of bright extrasolar giant planets (EGP) with VSI.