Mechanical properties of suspended quasi-one-dimensional polymer nanostructures were investigated using atomic force microscopy (AFM). A recently developed new acid-free etch method combined with electron beam lithography was used to fabricate suspended polypyrrole (PPy) nanotubes and helical polyacetylene (HPA) nanofibres. The elastic modulus of each suspended structure was obtained by AFM force-distance measurements. The estimated modulus value of the PPy nanotube (HPA nanofibre) was 0.96 GPa (0.5 GPa). Using this acid-free method, all-organic flexible NEMS devices can be fabricated in the future.