Data
from the H2O Galactic Plane Survey (HOPS) and additional Mopra mm
observations have been used to search for dense gas toward
unidentified Galactic TeV gamma-ray sources seen by the High Energy
Spectroscopic System (H.E.S.S.). Previous searches for counterparts
have
concentrated on large scale molecular and atomic gas, aiming
to determine if they arise from acceleration cosmic-rays and/or
electrons. However the morphology and dynamics of dense gas can
provide additional insight into the conditions of the ISM towards the
gamma-ray emission. In this work, dense and disrupted molecular gas
traced at 12 mm wavelengths has been used to provide further insight
to the origin of several bright unidentified TeV sources.