Gamma ray bursts (GRBs) are energetic, transient explosions, which indicate either death of a massive star $\rm (\ge 25 M_{\odot})$ or merger of two compact object. In the current
understanding, collapsar based GRBs stay active for long duration $\rm (T_{90}>2s)$, and merger based GRBs last for very short duration $\rm (T_{90} < 2s)$, $\rm T_{90}$ is the time over which
gamma ray burst emits 90 $\%$ of its total measured fluence. A clear understanding of GRB emission can reveal, nature of the central source and the composition of the relativistic jet.
Fermi-LAT observations of GRBs have detected a significant power law component in the energy range MeV to $\rm >10's$ of GeV, in short as well as in long GRBs.
The explanation of its origin is still not understood. In this work we have discussed plausible origin of this component, in the case for long GRBs.