If the appropriate Government is satisfied that having regard to an establishment or a class of establishments providing for the grant of benefits which are not less favourable than those provided in this Act, it is necessary so to do, it may, by notification in the Official Gazette, exempt, subject to such conditions and restrictions, if any, as may be specified in the notification, the establishment or class of establishments from the operation of all or any of the provisions of this Act or of any rule made thereunder.