  We report on the first near-IR [Fe II] line imaging survey of extragalactic
  SNRs.
  Observations of a sample of 42 objects drawn from an optically-selected
catalogue of SNRs in M33 provide evidence for a wide range in the [Fe II] 1.644
microns luminosities. This can be understood as being primarily due to
variations in the chemical abundances and density of the local ISM, although
shock conditions may also play a significant role. We briefly discuss how these
results may be used to better calibrate the supernova rate of star-forming
galaxies.
