  We present long-slit spectrophotometric observations in the red and near
infrared of 12 HII galaxies. The spectral range includes the sulphur lines
[SII] at wavelengths 6716, 6731 angstroms and [SIII] at 6312 angstroms and
9069, 9532 angstroms. For all of the observed galaxies, at least three
ion-weighted temperatures from forbidden auroral to nebular line ratios have
been obtained and the relations between the different line temperatures have
been discussed. It is found that, for some objects, the [OII] temperatures
derived from those of [OIII] through the use of photo-ionisation models,
without taking into account the effect of density, can lead to a significant
underestimate of the O+/H+ ionic abundance and hence of the total oxygen
abundance.
