The different scenarios of spontaneous breaking of D parity have been studied in both the nonsupersymmetric and the supersymmetric version of the left-right symmetric models (LRSM). We explore the possibility of a TeV scale SU(2)R breaking scale MR and hence TeV scale right-handed neutrinos from both minimization of the scalar potential as well as the coupling constant unification point of view. We show that, although minimization of the scalar potential allows the possibility of a TeV scale MR and tiny neutrino masses in LRSM with spontaneous D-parity breaking, the gauge coupling unification at a high scale ∼1016 GeV does not favor a TeV scale symmetry breaking except in the supersymmetric left-right model with Higgs doublet and bidoublet...