Given an orbit space of matrices $M/\Gamma$ and an equivalence relation defined in it by means of the action of a group $G$, we obtain a miniversal deformation of an orbit through a minivesal deformation in $M$ with regard to a suitable group action of $G\times \Gamma$. We show some applications to the perturbations of $m$-tuples of subspaces and $(C,A)$-invariant subspaces.