The Office of Cambodia has recently informed WIPO that holders of international registration containing a designation of Cambodia will have to file a declaration of actual use of the mark with evidence to that effect.
The declarations must be filed (upon payment of a fee) directly to the Cambodian Office within one year following the five years counted from the date on which protection was granted in Cambodia, or within one year following the five years from the date of each renewal of the international registration.
Source: http://www.wipo.int