(1) Summons for the attendance of any person, whether a party or witness at an inquiry or other proceedings under the Act may be sent to him by post or a special messenger selected by the Administrator-General or in any other manner which he thinks fit. The summons may be substituted by a letter of request where the person to be summoned is, in the opinion of the Administrator-General, of a rank entitling him to such mark of consideration. The letter of request shall contain all the particulars required to be stated in a summons and, shall be treated in all respects as a summons. The summons or letter of request shall be deemed to have been duly served on the person summoned if it is sent by registered post and an acknowledgement or refusal thereof has been received.
(2) All summonses, letters of request and other processes may be signed by the Administrator-General, or such officer as he appoints for the purpose.
(3) No summons or letter of request for the attendance of any witness shall be issued at the instance of a party to an inquiry or other proceeding under the Act, unless the party within fourteen days of demand deposits with the Administrator-General such sum of money as in the opinion of the Administrator-General is sufficient to defray the travelling and other expenses, payable, to such witnesses.