  We present new spectroscopic observations of the southern radio galaxy
PKS1549-79 (z =0.152).Despite the flat spectrum character of the radio emission
from this source, our optical spectra show no sign of the broad permitted lines
and non-stellar continuum characteristic of quasar nuclei and broad line radio
galaxies. However, the high ionization forbidden lines, including
[OIII]5007,4959, are unusually broad for a narrow line radio galaxy (FWHM 1350
km/s), and are blueshifted by 600 km/s relative to the low ionization lines
such as[OII]3726,3729. The [OII] lines are also considerably narrower (FWHM 650
km/s) than the [OIII] lines, and have a redshift consistent with that of the
recently-detected HI 21cm absorption line system. Whereas the kinematics of the
[OIII] emission lines are consistent with outflow in an inner narrow line
region, the properties of the [OII] emission lines suggest that they are
emitted by a more extended and quiescent gaseous component. We argue that,
given the radio properties of the source, our line of sight is likely to be
lying close to the direction of bulk outflow of the radio jets. In this case it
is probable that the quasar nucleus is entirely obscured at optical wavelengths
by the material responsible for the HI absorption line system.The unusually
broad [OIII] emission lines suggest that the radio source is intrinsically
compact. Overall, our data are consistent the idea that PKS1549-79 is a radio
source in an early stage of evolution.
