This paper reports on the synthesis and structure elucidation of the track-etched membranes with embedded gold nanotubes (prepared in etched-only and COOH-enriched PET track-etched membranes) as well as comparative testing of the catalytic activity of prepared composites. The carboxylic group functionality was enriched by successive oxidation by hydrogen peroxide and UV. "As-prepared" and oxidized membrane composites were examined for catalytic activity using reduction of 4-nitrophenol (4-NP) by NaBH4. The catalytic activity of Au/PET-Ox composite was found to be 23% more effective than Au/PET-Etch composites. Nanocomposites were also investigated by XRD, XPS and SEM techniques.