Benhamipolynoe cairnsi is known from the south-west Pacific Ocean from depths of about 400âÂÂ500m
Benhamipolynoe cairnsi has 10 pairs of elytra (fewer than Benhamipolynoe antipathicola) and the preserved specimens studied thus far are not known to be pigmented.
Benhamipolynoe cairnsi has a commensal relationship with the stylasterid coral Conopora adeta.