Clad-modified fibre optic ammonia sensor was developed subsequently using pure V2O5, MoO3, and its composites with TiO2. Prior to the sensing measurement, the composite was synthesised and studied for the structural and microstructural properties using powder X-ray diffractometer and field emission scanning electron microscope. The analysis confirms the existence of nanocrystalline anatase phase TiO2 in the grain boundaries of microcrystalline V2O5/MoO3 in the composites. Ammonia sensing measurement was performed for different concentrations of ammonia exposures up to 500 ppm. The obtained response was applied to calculate the sensitivity and it was found to be superior for the clad modified with composite material as compared to the pure microcrystalline samples are discussed in detail. © 2019The Institution of Engineering and Technology.