Near-lattice-matched GaN/AlInN multiple quantum wells (MQWs) are investigated by means of the diamond anvil cell high-pressure technique. The hydrostatic pressure dependence of the photoluminescence dE(PL)/dp and the variation in the PL peak energy with the QW width for different pressures were measured. Taking into account the influence of a large Stokes shift on the correct determination of the built-in electric field value, we find that the electric field, equal to 4.2 +/- 1.1 MV/cm at ambient pressure, increases with pressure at a rate of 0.29 MV/(cm GPa). This value is in reasonable agreement with the theoretically predicted value, based on nonlinear elasticity, of 0.17 MV/(cm GPa). Interestingly, the observed behavior is very similar to strongly mismatched GaN/AlGaN QWs with a similar band offset, indicating that in GaN/AlInN QWs there is still a pressure dependence of piezoelectric effects, in spite of ambient-pressure lattice matching. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2977608]