2The chairman and other members shall hold office for a period which, in the case of each of the members first appointed and of any member appointed to fill a casual vacancy, shall be of such duration not exceeding five years as may be determined by the Minister, and in the case of all other members shall be a period of five years :
Provided that any member may by notice in writing to the Minister resign office at any time and shall be eligible for re-appointment from time to time on or after the expiration of his term of office.