(1) Save as otherwise provided in this section, the term of office of a member shall be five years and shall commence from the date of the notification of his election or nomination under section 12 or from the date on which the vacancy in which he is elected or nominated has occurred, whichever date is later:
     Provided that the Adminstrator may, when satisfied that it is necessary in order to avoid administrative difficulty, extend the term of office of all the members by such period not exceeding one year as he thinks fit.
     (2) The term of office of a member elected to fill a casual vacancy shall commence from the date of the notification of his election and shall continue so long only as the member in whose place he is elected would have been entitled to hold office if the vacancy had not occurred.