  Recently topologically non-trivial phases have been identified in few
time-reversal invariant systems that lack of inversion symmetry. Using density
functional theory based first-principles calculations, we report a strong
topologically non-trivial phase in chalchopyrite ZnGeSb$_2$, which can act as a
model system of strained HgTe. The calculations reveal the non-zero topological
invariant ($Z_2$), the presence of Dirac cone crossing in the surface spectral
functions with spin-momentum locking. We also show that the application of
moderate hydrostatic pressure ($\sim$7 GPa) induces topological phase
transition from topological non-trivial phase to a topologically trivial phase.
A discontinuity in the tetragonal distortion of non-centrosymmetric ZnGeSb$_2$
plays a crucial role in driving this topological phase transition.
