A novel approach was developed to investigate the applicability of green-synthesised tellurium nanoparticles (Te-NPs) for the conservation of historical oil paintings from the effects of bacteria. The Te-NPs were produced using two eco-friendly methods. The Te-NPs prepared with polyvinylpyrrolidone (PVP) and ascorbic acid (AP-Te-NPs) and the Te-NPs synthesised with Pluchea dioscoridis extract (PE-Te-NPs) were characterised using transmission electron microscopy (TEM) and X-ray diffraction (XRD) to confirm the formation of the Te-NPs. The antibacterial activities of Te-NPs, blank mock-up painting models (MPMs), and Te-NPs treated MPMs (0.1-5 mM) were evaluated against Gram-positive and Gram-negative bacteria. Scanning electron microscopy (SEM) was used to examine the MPMs that were degraded by the tested bacteria. The cytotoxicity of the Te-NPs was evaluated. In addition, the colour properties of the MPMs were determined to evaluate the effects of the produced Te-NPs on the MPMs. The Te nanorods had lengths ranging from 5-102 nm, and diameters between 1 and 11.5 nm. In addition, Te-NPs with spherical and flower-like shapes ranged from 3.4 to 17.9 nm. Te-NPs showed excellent antibacterial activity, especially against Gram-negative bacteria. PE-Te-NPs showed higher antibacterial activity against the tested bacteria than AP-Te-NPs. SEM micrographs and colour measurements revealed that the use of Te-NPs significantly minimised the harmful effects of the tested bacteria on MPMs surfaces. The cytotoxicity test also confirmed the potential applicability of Te-NPs (1 mM) as a sustainable agent for the conservation of historical oil paintings.