We perform the flavour $SU(3)$ analysis of the recently discovered $Omega(2012)$ hyperon. We find that well known (four star) $Delta(1700)$ resonance with quantum numbers of $J^P=3/2^-$ is a good candidate for the decuplet partner of $Omega(2012)$ if the branching for the three-body decays of the latter is not too large $le 70$%. That implies that the quantum numbers of $Omega(2012)$ are $I(J^P)=0(3/2^-)$. The predictions for the properties of still missing $Sigma$ and $Xi$ decuplet members are made. We also discuss the implications of the ${ overline{ K} Xi(1530)}$ molecular picture of $Omega(2012)$. Crucial experimental tests to distinguish various pictures of $Omega(2012)$ are suggested.