—(1) Every notice, order or document required or authorised by this Act to be served on any person may be served —
by delivering it to the person or to some adult member or employee of his family or his household at his last known place of residence;
by leaving it at his usual or last known place of residence or business in an envelope addressed to him; or
by sending it by ordinary or registered post addressed to the person at his usual or last known place of residence or business.
(2) Where any notice, order or document is served by ordinary or registered post, it shall be deemed to have been duly served at the time it would have been received in the ordinary course of post if the notice, order or document is addressed —
in the case of a company incorporated in Singapore, to the registered office of the company;
in the case of a company incorporated outside Singapore, either to the individual authorised to accept service of process under the Companies Act (Cap. 50) at the address filed with the Registrar of Companies, or to the registered office of the company wherever it may be situated;
in the case of an individual, a partnership (including a limited liability partnership as defined in section 4(1) of the Limited Liability Partnerships Act (Cap. 163A)) or a body of persons, to the last known business or private address of such individual, partnership or body of persons.
(3) Where any notice, order or document is served by registered post in accordance with subsection (2), in proving service of the notice, order or document, it shall be sufficient to prove that the envelope containing the same was properly addressed, stamped and posted by registered post.
(4) Every notice, order or document to be given by the Controller or an employment inspector under this Act shall be signed by the Controller or employment inspector, or by some person or persons from time to time authorised by the Controller or employment inspector, as the case may be, in that behalf, and every such notice, order or document shall be valid if the signature or an official facsimile thereof of the Controller, employment inspector or such person or persons is duly printed or written thereon.
(5) Any notice or order under this Act requiring the attendance of any person or witness before the Controller or an employment inspector shall be signed by the Controller or the employment inspector, as the case may be, or by a person duly authorised by the Controller.