We present long-slit observations in the red and near infrared of 12 HII galaxies made with the Isaac Newton Telescope at the Roque de los Muchachos Observatory in 1999 February and 2000 January. The spectral range includes the sulphur lines [SII] at 6717, 6731 Å and [SIII] at 9069, 9532 Å. For all the observed galaxies, ion-weighted temperatures from optical forbidden auroral to nebular line ratios have been obtained in order to study the inner ionization structure of these high excitation objects, as well as the oxygen and sulphur abundances.