  A method based on flavour SU(3) is proposed for identifying and extracting
New Physics (NP) amplitudes in charmless $\Delta S=1$ $B_s$ decays using
time-dependent CP asymmetries in these decays and in flavour SU(3) related
$\Delta S=0$ decays. For illustration, we assume a hierarchy, $\sim 1: \lambda
: \lambda^2$ ($\lambda=0.2$), between a dominant $\Delta S=1$ penguin
amplitude, a NP amplitude and a Standard Model amplitude with weak phase
$\gamma$. An uncertainty from SU(3) breaking corrections, reduced by using
ratios of hadronic amplitudes, is further suppressed by a factor $\lambda$. We
discuss examples for pairs of decays into two neutral vector mesons,
$B_s\to\phi\phi, B_s\to\phi \bar K^{*0}$ and $B_s\to K^{*0}\bar K^{*0}, B^0\to
K^{*0}\bar K^{*0}$, where the magnitude of the NP amplitude, its weak and
strong phases can be determined.
