In the current precision era of neutrino physics, the subdominant new physics scenarios, such as non-standard interactions (NSI) are of great interest for exploring physics beyond the standard model (BSM). Scalar NSI (SNSI), which is mediated by a scalar field, has been a fascinating area of study in recent times. SNSI modifies the standard neutrino mass matrix through the Yukawa couplings and appears as an additional contribution to the mass matrix. We investigate the effect of complex off-diagonal SNSI parameters, which are characterized by their magnitudes \(\eta _{\alpha \beta }\) and new phases \(\phi _{\alpha \beta }\) . We then demonstrated the correlation between different oscillation parameters and found that \(\Delta m^2_{31}\) exhibits non-trivial behaviour when SNSI parameters are present. Additionally, we noticed that \(\eta _{\mu \tau }\) plays an important role in the determination of various oscillation parameters.