via airmail, usually the Hong Kong custom don’t have any problems, problems will be with the Express courier . If they label it as an airsoft product the courier like UPS will be scar and they will sent it back to the sender before handling it to the Australian custom. Just tell them to sent it by normal mail and don’t label it with “airsoft” on the declaration. Or try other Hong Kong airsoft supplier like Tiger111HK, Sixmm (usually they sent it by normal mail have no problem at all)