  We show that Spatially Inhomogeneous (SI) and Irrotational dust models admit
a \emph{6-dimensional algebra } of \emph{Intrinsic Conformal Vector Fields}
(ICVFs) $\mathbf{X}_{\alpha }$ satisfying
$p_{a}^{c}p_{b}^{d}\mathcal{L}_{\mathbf{X}_{\alpha }}p_{cd}=2\phi
(\mathbf{X}_{\alpha })p_{ab}$ where $p_{ab}$ is the associated metric of the 2d
distribution $\mathcal{X}$ normal to the fluid velocity $u^{a}$ and the radial
unit spacelike vector field $x^{a}$. The Intrinsic Conformal (IC) algebra is
determined for each of the curvature value $\epsilon $ that characterizes the
structure of the screen space $\mathcal{X}$. In addition the conformal flatness
of the hypersurfaces $\mathbf{u}=\mathbf{0}$ indicates the existence of a
\emph{% 10-dimensional algebra} of ICVFs of the 3d metric $h_{ab}$. We
illustrate this expectation and propose a method to derive them by giving
explicitly the \emph{7 proper} ICVFs of the Lema\^{\i}tre-Tolman-Bondi (LTB)
model which represents the simplest subclass within the Szekeres family.
