  We study the size and shape of low density regions in the local universe
which we identify in the smoothed density field of the PSCz flux limited IRAS
galaxy catalogue. After quantifying the systematic biases that enter in the
detection of voids using our data set and method, we identify, using a
smoothing length of 5 $h^{-1}$ Mpc, 14 voids within 80 $h^{-1}$ Mpc and using a
smoothing length of 10 $h^{-1}$ Mpc, 8 voids within 130 $h^{-1}$ Mpc. We study
the void size distribution and morphologies and find that there is roughly an
equal number of prolate and oblate-like spheroidal voids. We compare the
measured PSCz void shape and size distributions with those expected in six
different CDM models and find that only the size distribution can discriminate
between models. The models preferred by the PSCz data are those with
intermediate values of $\sigma_{8} (\simeq 0.83)$, independent of cosmology.
