The kinetic changes in the growth of GaN induced by the presence of In segregated on the surface has been investigated in-situ by using high energy electron diffraction intensity oscillations. Two types of surfaces have been studied, namely Ga-polar (0001) wurzite, and (001) zinc blende. It has been found that In influenced both Ga and N surface kinetics leading to a change in the growth rate associated with a change in the amount of Ga and N effectively available for the GaN growth.