In this work, we proposed a hybrid plasmonic waveguide for bulk index sensing, which is compatible with Mach-Zehnder interferometer sensing arrangement. The modal properties of the guiding geometry are investigated using the finite element method. This waveguide supports a long-ranging hybrid plasmon mode, which is highly confined in nanofluidic analyte channel due to the optical capacitance effect. Thus, an improved biosensing performance is demonstrated with high Figure of merit at the telecommunication wavelength. The sensing performance is also analyzed here for a broad range of operating wavelength in order to examine the multiwavelength operability of the proposed hybrid plasmonic waveguide biosensor.