  We study the new physics contributions to neutrinoless double beta decay
($0\nu\beta\beta$) in a TeV scale left-right model with spontaneous D-parity
breaking mechanism where the values of the $SU(2)_L$ and $SU(2)_R$ gauge
couplings, $g_L$ and $g_R$ are unequal. Neutrino mass is generated in the model
via gauge extended inverse seesaw mechanism. We embed the model in a
non-supersymmetric $SO(10)$ GUT with a purpose of quantifying the results due
to the condition $g_{L} \neq g_{R}$. We compare the predicted numerical values
of half life of $0\nu\beta\beta$ decay, effective Majorana mass parameter and
other lepton number violating parameters for three different cases; (i) for
manifest left-right symmetric model ($g_L = g_R$), (ii) for left-right model
with spontaneous D parity breaking ($g_L \neq g_R$), (iii) for Pati-Salam
symmetry with D parity breaking ($g_L \neq g_R$). We show how different
contributions to $0\nu\beta\beta$ decay are suppressed or enhanced depending
upon the values of the ratio $\frac{g_R}{g_L}$ that are predicted from
successful gauge coupling unification.
