The pressure dependence of the components of the recombination current at threshold in 1.3-mum GaInNAs single quantum-well lasers is presented using for the first time high-pressure spontaneous emission measurements up to 13 kbar. It is shown that, above 6 kbar, the rapid increase of the threshold current With increasing pressure is associated with the unusual increase of the Auger-related nonradiative recombination current, while the defect-related monomolecular nonradiative recombination current is almost constant. Theoretical calculations show that the increase of the Auger current can be attributed to a large increase in the threshold carrier density with pressure, Which is mainly due to the increase in the electron effective mass arising from the enhanced level-anticrossing between the GaInNAs conduction band and the nitrogen level.