Continuous depth sensing nano-indentation hardness measurements coupled with low-energy positron beam Doppler broadening line shape measurements were performed to investigate the influence of vacancy defects on mechanical properties in as-dealloyed and Fe+ ion irradiated nanoporous Au. A linear relationship has been obtained from the actual data between the nano-indentation hardness and square root of the concentration of defects. It suggests that the vacancy-type defects that evolved in the ligaments play a significant role in the modification of mechanical properties in both as-dealloyed and Fe+ ion irradiated nanoporous Au. The results have been also compared with those obtained on bulk Au. Copyright (C) EPLA, 2020