The precise compositional analysis of tritium-containing gases is of high interest for tritium accountancy, e.g. in future fusion power plants. Raman spectroscopy provides a fast and contact-free gas analysis procedure with high precision, thus being an advantageous tool for the named purpose. In this paper, it is shown that the sensitivity achieved with conventional Raman systems (in 90° or forward/backward configurations) can be enhanced by at least one order of magnitude by using a metal-lined hollow glass fiber as the Raman cell. This leads to the ability to detect low partial pressures of tritium within short measurement intervals (< 0.5 mbar in < 0.5 s).