  One of the most interesting channels to search for SUSY is the direct
pair-production of the $\tau$-lepton superpartner, $\widetilde{\tau}$. The
$\widetilde{\tau}$ is with high probability the lightest of the scalar leptons,
so one of the first SUSY particles that can be observerd, and the signature of
$\widetilde{\tau}$ pair production signal events is one of the most difficult
ones, yielding to the ``worst'' and so most global scenario for the searches.
Analysis performed at LEP set the current model-independent $\widetilde{\tau}$
limits, suffering from the low energy of this facility. Only under strong model
assumptions, these limits are extended to higher masses by LHC studies. In this
contribution we show the capability of the ILC, a future electron-positron
collider with energy up to 1 TeV, for determining $\widetilde{\tau}$
exclusion/discovery limits in a model-independent way, including an overview of
the current state-of-the-art. The determination of the ``worst'' scenario for
$\widetilde{\tau}$ exclusion/discovery, taking into account the effect of the
$\widetilde{\tau}$ mixing on $\widetilde{\tau}$ production cross-section and
efficiency, is also presented. For selected benchmarks, the prospect for
measuring masses and polarised cross-sections will be shown. The studies were
done studying events passed through the full detector simulation and
reconstruction procedures of the International Large Detector (ILD) concept at
the ILC. The simulation included all SM backgrounds, as well as the machine
induced ones.
