  In this work, we investigate the impact of neutrino decay in the presence of
Non-Standard Interactions (NSI) along with the effects of the Majorana phase on
neutrino decay in matter in the context of two-flavor neutrino oscillations.
These effects are studied on neutrino oscillation probabilities $P_{\alpha
\beta} \equiv P(\nu_{\alpha} \to \nu_{\beta})$, and the difference $\Delta
P_{\alpha \beta} \equiv P(\nu_{\alpha} \to \nu_{\beta}) - P(\bar {\nu}_{\alpha}
\to \bar{\nu}_{\beta})$ for several accelerator and reactor neutrino
experiments. We find that for $P_{\alpha \beta}$, the influence of the Majorana
phase on decay in matter can be replicated by the simultaneous presence of both
decay and NSI. However, precise measurements of the $P_{\alpha \beta}$ and
$\Delta P_{\alpha\beta}$ observables have the potential to unequivocally
identify the presence of the Majorana phase by discerning its effects from the
concurrent presence of both decay and NSI.
