Green nanotechnology plays a significant role in developing effective treatment strategies for numerous diseases. The biological synthesis of metal nanoparticles (M-NPs) possesses suitable alternatives than chemical techniques. Using plant extract to synthesis M-NPs is an eco-friendly, non-toxic, and cost-effective that are suitable for biological applications and efforts are directed to explore the efficacy of these materials in cancer management. In this study, gold nanoparticles (Au-NPs) were synthesised by following a one-step green synthesis, a reaction between HAuCl4 and biological molecules present in Tasmannia lanceolata leaf extract as a sole agent for both reduction and stabilisation. The characterisation techniques confirmed the successful synthesis of Au-NPs. TEM photograph revealed spherical shape nanoparticles with an average size of 7.10 ± 0.66 nm. The in-vitro cytotoxicity of Au-NPs was performed by analysing the percentage inhibition of cell viability using Resazurin assay on human liver cancer (HepG2), melanoma cancer (MM418 C1) and breast cancer (MCF-7) cell lines and compared with Au-NPs synthesised by using Backhousia citriodora leaf extract. The results showed that biosynthesised Au-NPs displayed greater inhibitory activity towards MCF-7 cancer cells proliferation compared to HepG2 and MM418 cancer cells. In addition, synthesised Au-NPs@ Tasmannia lanceolata leaf extract indicated higher inhibitory activity towards cancer cells compared to Au-NPs@ Backhousia citriodora leaf extract.